PKIX M. Pritikin, Ed. Internet-Draft Cisco Systems, Inc. Intended status: Standards Track P. Yee, Ed. Expires: January 11, 2013 AKAYLA, Inc. D. Harkins, Ed. Aruba Networks July 10, 2012 Enrollment over Secure Transport draft-ietf-pkix-est-02 Abstract This document profiles certificate enrollment for clients using Certificate Management over CMS (CMC) messages over a secure transport. This profile, called Enrollment over Secure Transport (EST), describes a simple yet functional certificate management protocol targeting simple Public Key Infrastructure clients that need to acquire client certificate(s) and associated Certification Authority (CA) certificate(s). Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 11, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Pritikin, et al. Expires January 11, 2013 [Page 1] Internet-Draft EST July 2012 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 2. Operational Scenario Overviews . . . . . . . . . . . . . . . . 5 2.1. Obtaining CA Certificates . . . . . . . . . . . . . . . . 6 2.2. Initial Enrollment . . . . . . . . . . . . . . . . . . . . 6 2.2.1. Previously Installed Signature Certificate . . . . . . 7 2.2.2. Username/Password Distributed Out-of-Band . . . . . . 7 2.2.3. RA Authentiation . . . . . . . . . . . . . . . . . . . 7 2.3. Re-Enrollment . . . . . . . . . . . . . . . . . . . . . . 7 2.3.1. Re-Enrollment of Signature Certificates . . . . . . . 7 2.3.2. Re-Enrollment of Key Establishment Certificates . . . 8 2.4. Server Key Generation . . . . . . . . . . . . . . . . . . 8 2.5. Full CMC messages . . . . . . . . . . . . . . . . . . . . 8 2.6. CSR Attributes Request . . . . . . . . . . . . . . . . . . 8 3. Protocol Design and Layering . . . . . . . . . . . . . . . . . 8 3.1. Application Layer Design . . . . . . . . . . . . . . . . . 11 3.2. HTTP Layer Design . . . . . . . . . . . . . . . . . . . . 12 3.2.1. HTTP headers for control . . . . . . . . . . . . . . . 12 3.2.2. HTTP URIs for control . . . . . . . . . . . . . . . . 13 3.2.3. HTTP-Based Client Authentication . . . . . . . . . . . 14 3.2.4. Message types . . . . . . . . . . . . . . . . . . . . 15 3.3. TLS Layer Design . . . . . . . . . . . . . . . . . . . . . 16 3.3.1. TLS for transport security . . . . . . . . . . . . . . 16 3.3.1.1. TLS-Based Server Authentication . . . . . . . . . 16 3.3.1.2. TLS-Based Client Authentication . . . . . . . . . 17 3.4. Proof-of-Possession . . . . . . . . . . . . . . . . . . . 17 3.5. Linking Identity and POP information . . . . . . . . . . . 18 4. Protocol Exchange Details . . . . . . . . . . . . . . . . . . 19 4.1. Server Authorization . . . . . . . . . . . . . . . . . . . 19 4.2. Client Authorization . . . . . . . . . . . . . . . . . . . 20 4.3. Distribution of CA certificates . . . . . . . . . . . . . 20 4.3.1. Distribution of CA certificates response . . . . . . . 21 4.4. Simple Enrollment of Clients . . . . . . . . . . . . . . . 22 4.4.1. Simple Re-Enrollment of Clients . . . . . . . . . . . 23 4.4.2. Simple Enroll and Re-Enroll Response . . . . . . . . . 24 4.5. Full CMC . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.5.1. Full CMC Request . . . . . . . . . . . . . . . . . . . 25 4.5.2. Full CMC Response . . . . . . . . . . . . . . . . . . 25 4.6. Server-side Key Generation . . . . . . . . . . . . . . . . 26 Pritikin, et al. Expires January 11, 2013 [Page 2] Internet-Draft EST July 2012 4.6.1. Server-side Key Generation Request . . . . . . . . . . 26 4.6.2. Server-side Key Generation Response . . . . . . . . . 26 4.7. CSR Attributes . . . . . . . . . . . . . . . . . . . . . . 27 4.7.1. CSR Attributes Request . . . . . . . . . . . . . . . . 27 4.7.2. CSR Attributes Response . . . . . . . . . . . . . . . 27 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 6. Security Considerations . . . . . . . . . . . . . . . . . . . 30 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32 7.1. Normative References . . . . . . . . . . . . . . . . . . . 32 7.2. Informative References . . . . . . . . . . . . . . . . . . 33 Appendix A. Server Discovery . . . . . . . . . . . . . . . . . . 34 Appendix B. External TLS concentrator . . . . . . . . . . . . . . 34 Appendix C. CGI Server implementation . . . . . . . . . . . . . . 35 Appendix D. Operational Scenario Example Messages . . . . . . . . 35 D.1. Obtaining CA Certificates . . . . . . . . . . . . . . . . 35 D.2. Previously Installed Signature Certificate . . . . . . . . 36 D.3. Username/Password Distributed Out-of-Band . . . . . . . . 38 D.4. Re-Enrollment . . . . . . . . . . . . . . . . . . . . . . 41 D.5. Server Key Generation . . . . . . . . . . . . . . . . . . 42 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 46 Pritikin, et al. Expires January 11, 2013 [Page 3] Internet-Draft EST July 2012 1. Introduction This document specifies a protocol for certificate Enrollment over Secure Transport (EST). EST is designed to be easily implemented by clients and servers using common "off the shelf" PKI, HTTP, and TLS components. An EST server providing certificate management functions is operated by (or on behalf of) a CA or RA. The goal is to provide a small set of functions for certificate enrollment that are simpler to implement and use than full CMP or CMC. While less functional than those protocols, EST satisfies basic needs by providing an easily implemented means for both autonomous devices as well as user- operated computers to request certificates. The TLS [RFC4346] (or later) protocol is used with a limited set of features of the Certificate Management over CMS (CMC) [RFC5272] to provide the security for EST. CMC "simple" messages are used for certificate requests and responses. EST also allows the optional use of "full" CMC messages if needed, but compliant EST client and server implementations need not support full CMC messages. EST adopts the CMP model for CA certificate rollover, but does not incorporate its syntax or protocol. An EST server supports several means of authenticating a certificate requester, leveraging the layering of the protocols that make up EST. EST servers are extensible in that new requests may be defined which provide additional capabilities not specified in the base RFC. One non-CMC-based extension (requesting of CSR attributes) is defined in this document. EST works by transporting CMC and other messages securely over an HTTPS transport in which HTTP headers and content types are used in conjunction with TLS security. TCP/IP sits under HTTPS; this document does not specify EST over DTLS or UDP. Figure 1 shows how the layers build upon each other. Pritikin, et al. Expires January 11, 2013 [Page 4] Internet-Draft EST July 2012 EST Layering: Protocols: +---------------------------------------------------+ | | | 4) EST messages for requests/responses | | | +---------------------------------------------------+ | | | 3) HTTP for message carriage and signaling | | | +---------------------------------------------------+ | | | 2) TLS for transport security | | | +---------------------------------------------------+ | | | 1) TCP/IP | | | +---------------------------------------------------+ Figure 1 [[EDNOTE: Comments such as this one, included within double brackets and initiated with an 'EDNOTE', are for editorial use and shall be removed as the document is polished.]] 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Operational Scenario Overviews This EST specification provides a profile of CMC using round-trip communication between the EST client and the EST server in which CMC "simple" messages are transmitted. The basic framework can be extended with additional capabilities that leverage the transport and security features supplied by EST. The EST server is assumed to be configured with an identity certificate and appropriate policy regarding authenticated clients. An EST server likely communicates with a CA for signing but for simplicity we indicate that a' certificate is signed' as if by the EST server. The EST client is initially configured with only the HTTPS URI of the EST server. Pritikin, et al. Expires January 11, 2013 [Page 5] Internet-Draft EST July 2012 This section illustrates several potential certificate enrollment and rekey scenarios supported by this profile. For clarity the EST client is assumed to perform "Obtaining CA Certificates" before performing other operations. This section does not intend to place any limits or restrictions on the use of full CMC. Sections 2.1-2.3 very closely mirror the exact text of the Scenarios Appendix of [RFC6403] with such modifications as are appropriate for this profile. (Our thanks are extended to the authors of that document). 2.1. Obtaining CA Certificates The EST client can request a copy of the current CA certificates. Following the logic laid out in Section 3.3.1.1 the EST client authenticates and authorizes the EST server. Available options include verifying the EST server URI against the EST server certificate (similar to a common HTTPS exchange), or using a "pinned" copy of the CA certificate. As a fallback the EST client can accept manual authentication performed by the end user (in which case the certificates received are be "pinned" for authenticating future communications with the EST server). Client authentication is not required for this exchange so it is trivially serviced by the EST server. 2.2. Initial Enrollment The EST client can enroll with the CA server by submitting an enrollment request to the EST server. Following the logic laid out in Section 3.3.1.1 the EST client authenticates and authorizes the EST server. Three scenarios for the EST server to authenticate the enrollment requests are: 1. Previously installed signature certificate (e.g., Manufacturer Installed Certificate or 3rd party issued certificate); 2. Username/password distributed out-of-band 3. RA authentication Pritikin, et al. Expires January 11, 2013 [Page 6] Internet-Draft EST July 2012 2.2.1. Previously Installed Signature Certificate If the EST client has a previously installed signature certificate issued by a trust anchor listed by the EST server during the TLS handshake it can be used to authenticate the request for a new certificate. The EST client responds to the TLS certificate request with the existing certificate as defined for TLS. The EST server will recognize the authorization of the previously installed certificate and issue an appropriate certificate to the EST client. 2.2.2. Username/Password Distributed Out-of-Band If the EST client did not have a previously installed signature certificate, or if the EST server wishes additional authentication information, the EST server requests the EST client submit a username/password using the HTTP authentication methods. 2.2.3. RA Authentiation In this scenario the EST client submits the certification request using either the /simpleEnroll or /fullCMC method. The EST server forwards the received request using either CMC or other methods out- of-scope of this document. 2.3. Re-Enrollment The EST client can renew/rekey an existing client certificate by submitting a re-enrollment request to the EST server. As for initial enrollment the EST server authenticates the client using any combination of the existing client certificate and an HTTP username/ password. Because the client specifically requests renew/rekey the EST server can adjust its policy accordingly. There are two scenarios to support the renew/rekey of clients that are already enrolled. One addresses the renew/rekey of signature certificates and the other addresses the renew/rekey of key establishment certificates. Typically, organizational policy will require certificates to be currently valid to be renewed/rekeyed, and it may require initial enrollment to be repeated when renew/rekey is not possible. 2.3.1. Re-Enrollment of Signature Certificates When a signature certificate is re-enrolled the existing certificate is used by the EST client for authentication. The EST server uses this information along with any supplimental HTTP authentication information and the certification request itself to determine the parameters of the certificate to issue in response. If there is no Pritikin, et al. Expires January 11, 2013 [Page 7] Internet-Draft EST July 2012 current signature certificate available the EST server can fallback on the HTTP authentication method. The certification request message will include the same Subject/SubjectAltName as the current signature certificate. 2.3.2. Re-Enrollment of Key Establishment Certificates When a key establishment certificate is re-enrolled an existing signature certificate is used by the EST client for authentication. The EST server uses this information along with any supplimental HTTP authentication information and the certification request itself to determine the parameters of the certificate to issue in response. If there is no current signature certificate available the EST server can fallback on the HTTP authentication method. The certification request message will include the same Subject/SubjectAltName as the current key establishment certificate. 2.4. Server Key Generation The EST client can request a server generated certificate and keypair. The EST server authenticates the client using any existing client signature certificate and/or HTTP username/password. 2.5. Full CMC messages Full CMC messages can be transported thus allowing access to functionality not provided by the simple CMC message. "Full" CMC messages are as defined in Sections 3.2 and 4.2 of [RFC5272]. Support for full CMC message transport is optional for EST clients and servers. 2.6. CSR Attributes Request Prior to sending an enrollment request to an EST server, an EST client may request that the EST server send it a (set of) additional attribute(s) that the client is requested to supply in the subsequent enrollment (certificate signing) request. 3. Protocol Design and Layering The following provides an expansion of Figure 1 describing how the layers are used. Each aspect is described in more detail in the sections below. Pritikin, et al. Expires January 11, 2013 [Page 8] Internet-Draft EST July 2012 EST Layering: Protocols and uses: +----------------------------------------------------+ | | | 3) Message types: | | - CMC "Simple PKI" messages | | (incorporating proof-of-possession) | | - CA certificate retrieval | | - "Full" CMC messages (optional) | | - CSR attribute request (optional) | | | +----------------------------------------------------+ | | | 2) HTTP: | | - HTTP headers and URIs for control | | - Content-Type headers specify message type | | - Headers for control/error messages | | - URIs for selecting operations | | - Basic authentication if no TLS client cert | | | +----------------------------------------------------+ | | | 1) TLS for transport security | | - Authentication for EST server and optionally | | EST client | | - Indirectly provides proof-of-identity for EST | | - Communications integrity | | - "Channel binding" to link proof-of-identity | | with message based proof-of-possession. | | (optional) | | | +----------------------------------------------------+ Figure 2 Specifying HTTPS as the secure transport for PKI enrollment messages introduces two 'layers' for communication of authentication and control messages during the protocol exchange: TLS and HTTP. The TLS layer provides message authentication and integrity during transport. The proof-of-identity is supplied by either the certificate exchange during the TLS handshake or within the HTTP layer headers. The message type along with control/error messages are included in the HTTP headers. The TLS and HTTP layer provided proof-of-identity means the CMC [RFC5272] Section 3.1 note that "the Simple PKI Request MUST NOT be Pritikin, et al. Expires January 11, 2013 [Page 9] Internet-Draft EST July 2012 used if a proof-of-identity needs to be included" is not applicable and thus the "Simple PKI" message types are used. The TLS layer certificate exchange provides a method for authorizing client enrollment requests using existing certificates. Such existing certificates may have been issued by the Certification Authority (CA) (from which the client is requesting a certificate) or they may have been issued under a distinct PKI (e.g., an IEEE 802.1AR IDevID [IDevID] credential). Proof-of-possession is a distinct issue from proof-of-identity and is included in the "Simple PKI" message type as described in Section 3.4. A method of linking proof-of-identiy and proof-of- posession is described in Section 3.5. This document also defines transport for the full CMC [RFC5272] specification compliant with CMC Transport Protocols [RFC5273]. During the protocol operations various different certificates can be used. The following table provides an informative overview. End entities MAY have one or more certificates of each type as is appropriate: Pritikin, et al. Expires January 11, 2013 [Page 10] Internet-Draft EST July 2012 Certificates/Trust-anchors and their corresponding uses: +--------------+--------------------+------------------------------+ | End Entity | Issuer | Use | +==============+====================+==============================+ | EST server | The CA served by | To authenticate | | | the EST server | servers that have certs | | | | issued by the CA | | | | Section: 3.3.1.1. | +--------------+--------------------+------------------------------+ | EST server | An unrelated CA | To authenticate | | | e.g., a Web site | servers that have certs | | | CA | issued by Web site CAs | | | | Section: 3.3.1.1. | +--------------+--------------------+------------------------------+ | EST client | Trust anchors for | EST clients can leverage | | Trust Anchor | third party CAs | a trust anchor database to | | Database | e.g., a list of | authenticate EST servers | | | Web site CA root | using a configured URI | | | certs | Section: 3.3.1.1 | +--------------+--------------------+------------------------------+ | EST client | An unrelated CA | To authenticate clients | | | e.g., a device | that have not yet enrolled | | | manufacturer | Section: 3.3.1.2 | +--------------+--------------------+------------------------------+ | EST client | The CA served by | To authenticate clients | | | the EST server | that have already enrolled | | | | (for re-enroll or obtaining | | | | additional certs) | | | | Section: 3.3.1.2 | +--------------+--------------------+------------------------------+ | EST client | The CA served by | Clients can obtain certs | | | the EST server | that can not be used for | | | | EST authentication | | | | (e.g., Key Encryption certs) | | | | Section: 4.4.1 | +--------------+--------------------+------------------------------+ Figure 3 3.1. Application Layer Design An EST client SHOULD have its own client certificate suitable for TLS client authentication (e.g., the digitalSignature bit is set). The client certificate, if available, is used when authenticating to the EST server. This certificate MAY also be used by the client with other certificate consuming protocols. If a client does not have a certificate, then the client MUST have HTTP Basic or Digest Pritikin, et al. Expires January 11, 2013 [Page 11] Internet-Draft EST July 2012 authentication credentials (see Section 3.2.3). HTTP authentication provides a bootstrap for clients that have not yet been issued an initial certificate. EST clients obtaining a certificates for other protocol purposes are RECOMMENDED to first obtain an appropropriate digitalSignature certificate for use when authenticating to the EST server. The client also SHOULD also have a CA certificate that will be used to authenticate the EST server. An EST client MUST be capable of generating and parsing simple CMC messages (see Section 4.4). Generating and parsing full CMC messages is optional (see Section 4.5). The client MUST also be able to request CA certificates from the EST server and parse the returned "bag" of certificates (see Section 4.3). Requesting CSR attributes and parsing the returned list of attributes is optional (see Section 4.7). 3.2. HTTP Layer Design HTTP is used to transport EST requests and responses. Specific URIs are provisioned for handling each type of request as described in Section 3.2.2. HTTP is also used for client authentication services when TLS client authentication is not available due to lack of a client certificate suitable for use by TLS, as detailed in Section Section 3.2.3. HTTP message types are used to convey EST requests and responses as specified in Figure 5. 3.2.1. HTTP headers for control This document profiles the HTTP content-type header (as defined in [RFC2046], but see Figure 5 for specific values ) to indicate the message type for EST messages and to specify EST control messages. The HTTP Status value is used to communicate success or failure of control messages. Support for the HTTP username/password methods is profiled for when a client does not have a suitable client certificate. CMC does not provide specific messages for certificate renewal and certificate rekey. This profile defines the renewal and rekey behavior of both the client and server. It does so by specifying the HTTP control mechanisms employed by the client and server without requiring a new CMC message type. Various media types as indicated in the HTTP content-type header are used to transport EST messages. Valid media types are specified in Section 3.2.4. Pritikin, et al. Expires January 11, 2013 [Page 12] Internet-Draft EST July 2012 3.2.2. HTTP URIs for control This profile supports four operations indicated by specific URIs: Operations and their corresponding URIs: +------------------------+-----------------+-------------------+ | Operation |Operation Path | Details | +========================+=================+===================+ | Distribution of CA | /CACerts | Section 4.3 | | certificates | | | +------------------------+-----------------+-------------------+ | Enrollment of new | /simpleEnroll | Section 4.4 | | clients | | | +------------------------+-----------------+-------------------+ | Re-Enrollment of | /simpleReEnroll | Section 4.4.1 | | existing clients | | | +------------------------+-----------------+-------------------+ | Full CMC (optional) | /fullCMC | Section 4.5 | +------------------------+-----------------+-------------------+ | Server-side Key | /serverKeyGen | Section 4.6 | | Generation (optional) | | | +------------------------+-----------------+-------------------+ | Request CSR attributes | /CSRAttrs | Section 4.7 | | (optional) | | | +------------------------+-----------------+-------------------+ Figure 4 An HTTP base path common for all of an EST server's requests is defined in the form of an path-absolute ([RFC3986], section 3.3). The operation path (Figure 4 is appended to the base path to form the URI used with HTTP GET or POST to perform the desired EST operation. An example: With a base path of "/arbitrary/path" and an operation path of "/CACerts", the EST client would combine them to form an absolute path of "/arbitrary/path/CACerts". Thus, to retrieve the CA's certificates, the EST client would use the following HTTP request: GET /arbitrary/path/CACerts HTTP/1.1 Likewise, to request a new certificate enrollment in this example scheme, the EST client would use the following request: POST /arbitrary/path/simpleEnroll HTTP/1.1 The mechanisms by which the EST server interacts with an HTTPS server Pritikin, et al. Expires January 11, 2013 [Page 13] Internet-Draft EST July 2012 to handle GET and POST operations at these URIs is outside the scope of this document. The use of distinct operation paths simplifies implementation for servers that do not perform client authentication when distributing "CACerts" responses. EST clients are to be provided with the URL of the EST server and the base path. The means by which clients acquire the URL and base path are outside the scope of this document. Whether the URL and base path are provided securely determines the authorization scheme required to perform operations. (See Section 4.1.) An EST server MAY provide additional, non-EST services on other URIs. An EST server MAY use multiple base paths in order to provide service for multiple CAs. Each CA would use a distinct base path, but operations are otherwise the same as specified for an EST server operating on behalf of only one CA. 3.2.3. HTTP-Based Client Authentication An EST server MAY fallback to using HTTP-based client authentication if TLS client authentication (Section 3.3.1.2) is not possible. Basic and Digest authentication MUST only be performed over TLS 1.1 [RFC4346] (or later). As specified in CMC: Transport Protocols [RFC5273] the server "MUST NOT assume client support for any type of HTTP authentication such as cookies, Basic authentication, or Digest authentication". Clients intended for deployments where password authentication is advantageous SHOULD support the Basic and Digest authentication mechanism. Servers MAY provide configuration mechanisms for administrators to enable Basic [RFC2616] and Digest [RFC2617] authentication methods. Servers that support Basic and Digest authentication methods MAY reject requests using the HTTP defined WWW-Authenticate response- header ([RFC2616], Section 14.47). At that point the client SHOULD repeat the request, including the appropriate Authorization Request Header ([RFC2617], Section 3.2.2) if the client is capable of using the Basic or Digest authentication. If the client is not capable then the client MUST terminate the connection. Clients MAY set the username to the empty string ("") if they wish to present a "one-time password" or "PIN" that is not associated with a username. Support for HTTP-based client authentication has security ramifications as discussed in Section 6. The client MUST NOT respond to this request unless the client has authenticated the EST server Pritikin, et al. Expires January 11, 2013 [Page 14] Internet-Draft EST July 2012 (as per Section 4.1). 3.2.4. Message types This document uses existing media types for the messages as specified by Internet X.509 Public Key Infrastructure Operational Protocols: FTP and HTTP [RFC2585] and The application/pkcs10 Media Type [RFC5967] and CMC [RFC5272]. To support distribution of multiple application/pkcs7-mime's for the CA certificate chain the [RFC2046] multipart/mixed media type is used. The message type is specified in the HTTP Content-Type header. The use herein is consistent with [RFC5273], with clarifications made concerning transfer encoding. For reference the messages and their corresponding MIME and media types are: +-------------------+--------------------------+-------------------+ | Message type |Request type | Request section | | |Response type | Response section | | |Source(s) of types | | +===================+==========================+===================+ | CA certificate | N/A | Section 4.3 | | request | application/pkcs7-mime | Section 4.3.1 | | | RFC 5751 | | +-------------------+--------------------------+-------------------+ | Cert enroll/renew | application/pkcs10 | Section 4.4/4.4.1 | | | application/pkcs7-mime | Section 4.4.2 | | | RFC 5967, RFC 5751 | | +-------------------+--------------------------+-------------------+ | Full CMC | application/pkcs7-mime | Section 4.5.1 | | | application/pkcs7-mime | Section 4.5.2 | | | RFC 5751 | | +-------------------+--------------------------+-------------------+ | Server-side Key | application/pkcs10 | Section 4.6.1 | | Generation | multipart/mixed | Section 4.6.2 | | | (application/pkcs7-mime &| | | | application/pkcs8) | | | | RFC 5967, RFC 5751 | | +-------------------+--------------------------+-------------------+ | Request CSR | N/A | Section 4.7.1 | | attributes | application/csrattrs | Section 4.7.2 | | | (Specified in this RFC) | | +-------------------+--------------------------+-------------------+ Figure 5 Pritikin, et al. Expires January 11, 2013 [Page 15] Internet-Draft EST July 2012 3.3. TLS Layer Design TLS provides communications security for the layers above it. Specifically, the integrity and authentication services it provides are leveraged to supply proof-of-identity and to allow authorization decisions to be made. TLS client authentication is the preferred method for identifying EST clients. In lieu of that, HTTP authentication protected by TLS encryption is also acceptable. Additionally, TLS channel binding information may be optionally inserted into a certificate request in order to provide the EST server with assurance that the authenticated TLS client entity has possession of the private key for the certificate being requested. HTTP 1.1 [RFC2616] and above support persistent connections. As given in Section 8.1 of that RFC persistent connections may be used to reduce network and processing load associated with multiple HTTP requests. EST does not require persistent HTTP connections and their use is out of scope of this specification. 3.3.1. TLS for transport security HTTPS is defined in HTTP Over TLS [RFC2818] and is a specification of how HTTP messages are carried over TLS. HTTPS (e.g., HTTP over TLS) MUST be used. TLS 'session resumption' SHOULD be supported. 3.3.1.1. TLS-Based Server Authentication The EST client MUST authenticate the EST server by validating the TLS server certificate the server presented during the TLS 1.1 [RFC4346] (or later) exchange-defined Server Certificate message or the client MUST independently validate the response contents. Validation is performed as given in [RFC5280] and [RFC6125]. There are multiple methods of validation depending on the current state of the client: Method 1) If the client has a store of trust anchors, which may be in the form of certificates, for authenticating TLS connections the client MAY validate the TLS server certificate using the standard HTTPS logic of checking the server's identity as presented in the server's Certificate message against the URI provisioned for the EST server (see HTTP Over TLS [RFC2818], Section 3.1 "Server Identity" and [RFC6125]). This method makes it possible for clients with a store of trust anchors to securely obtain the CA certificate by leveraging the HTTPS security model. The EST server URI SHOULD be made available to the client in a secure fashion so that the client only obtains EST functions from a desired server. Pritikin, et al. Expires January 11, 2013 [Page 16] Internet-Draft EST July 2012 Method 2) If the client already has one or more trust anchors associated with this EST server, the client MUST validate the EST server certificate using these trust anchors. The EST server URI MAY be made available to the client in an insecure fashion. The EST server certificate MUST contain the id-kp-cmcRA [CMC RFC5272bis] extended key usage extension. Method 3) If the client does not yet have a trust anchor associated with this EST server then the client MAY provisionally accept the TLS connection, but the HTTP content data MUST be accepted manually as described in Section 4.3. HTTP authentication requests MUST NOT be responded to since the server is unauthenticated (only the content data is accepted manually). Methods 1 and 2 are essentially validation as given in [RFC5280]. Method 1 is as described in [RFC6125], Section 6.6.1 "Match Found". Method 2 is described in [RFC6125] as "No Match Found, Pinned Certificate". Method 3 is described in [RFC6125], Section 6.6.4 as "Fallback" and describes the process of "pinning" the received certificate. If one of these validation methods succeeds, the CA certificate(s) are stored and "pinned" for future use. If none of these validation methods succeeds the client MUST reject the EST server response and SHOULD log and/or inform the end user. If Method 1 was used to authenticate the EST server then subsequent connections to the EST server also use Method 1. If Method 2 was used to authenticate the EST server then subsequent connections to the EST server also use Method 2. If Method 3 was used to manually authenticate the EST server then the EST client SHOULD "pin" the CA certificates received from a /CACerts (Section 4.3) operation and Method 2 is used for subsequent connections. 3.3.1.2. TLS-Based Client Authentication Clients SHOULD support [RFC4346]-defined (or later) Certificate request (section 7.4.4). As required by [RFC4346], the client certificate needs to indicate support for digital signatures. The client SHOULD support this method in order to leverage /simpleReEnroll using client authentication by existing certificate. If a client does not support TLS client authentication, then it MUST support HTTP-based client authentication. (Section 3.2.3) 3.4. Proof-of-Possession As defined in Section 2.1 of CMC [RFC5272], Proof-of-possession (POP) "refers to a value that can be used to prove that the private key Pritikin, et al. Expires January 11, 2013 [Page 17] Internet-Draft EST July 2012 coresponding to the public key is in the possession and can be used by an end-entity." The signed enrollment request provides a "Signature"-based proof-of- possession. The mechanism described in Section 3.5 strengthens this by optionally including "Direct"-based proof-of-possession by including TLS session specific information within the data covered by the enrollment request signature (thus linking the enrollment request to the authenticated end-point of the TLS connection). 3.5. Linking Identity and POP information This specification provides an optional method of linking identity and proof-of-possession by including information specific to the current authenticated TLS session within the signed certification request. This proves to the server that the authenticated TLS client has possession of the private key associated with the certification request and that the client was able to sign the certification request after the TLS session was established. This is an alternative to the [RFC5272] Section 6.3-defined "Linking Identity and POP information" method available if full CMC messages are used. The client generating the request SHOULD obtain the tls-unique value as defined in Channel Bindings for TLS [RFC5929] from the TLS subsystem. The tls-unique value is encoded as specified in Section 4 of Base64 [RFC4648] and the resulting string is placed in the certification request challenge-password field. If tls-unique information is not embedded within the certification request the challenge-password field MUST be empty. The tls-unique specification includes a synchronization issue as described in Channel Bindings for TLS [RFC5929] section 3.1. This problem is avoided for EST implementations. If the tls-unique value is used it MUST be from the first TLS handshake. EST client and servers use their tls-unique implementation specific synchronization methods to obtain this first tls-unique value. If identity linking is used then TLS renegotiation MUST use "secure_renegotiation" [RFC5746] (thus maintaining the binding). Mandating secure renegotiation secures this method of avoiding the synchronization issues encountered when using the most recent tls- unique value (which is defined as the the value from the most recent TLS handshake). The EST server MUST verify the tls-unique information embedded within the certification request and MUST reject requests with invalid tls- unique information. The EST server MAY be configured to accept requests from authenticated clients that do not include the tls- Pritikin, et al. Expires January 11, 2013 [Page 18] Internet-Draft EST July 2012 unique information. The tls-unique value is encoded into the certification request by the client but back-end infrastructure elements that process the request after the EST server might not have access to the initial TLS session. Such infrastructure elements validate the source of the certification request to determine if POP checks have already been performed. For example if the EST client authentication results in an authenticated client identity of an EST server RA that is known to independently verify the proof-of-possession then the back-end infrastructure does not need to perform proof-of-possession checks a second time. If the EST server forwards a request to a back-end process it SHOULD communicate the authentication results. This communication might use the CMC "RA POP Witness Control" in a CMC Full PKI Request message or other mechanisms which are out-of-scope of this document. [[EDNOTE: A specific error code (TBD) is returned indicating this additional linkage might be useful. This would be similar to the "WWW-Authenticate response-header" control message. Alternatively simply rejecting the request with an informative text message would work in many use cases.]] 4. Protocol Exchange Details Before processing a request, an EST server determines if the client is authorized to receive the requested services. Likewise, the client must make a determination if it will accept services from the EST server. Those determinations are described in the next two sections. Assuming that both sides of the exchange are authorized, then the actual operations are as described in the sections following. 4.1. Server Authorization The client MUST check the EST server authorization before accepting the server's response. The presented certificate MUST be an end- entity certificate such as a CMC Registration Authority (RA) certificate. There are multiple methods for checking authorization corresponding to the method of server authentication used (these authorization methods align with the authentication methods described in Section 3.3.1.1): Pritikin, et al. Expires January 11, 2013 [Page 19] Internet-Draft EST July 2012 Method 1) If the client authenticated the EST server using the client's TLS trust anchors store, then the client MUST have obtained the EST server's URI in a secure fashion. The client MUST check the URI "against the server's identity as presented in the server's Certificate message" (Section 3.1 "Server Identity" [RFC2818] and [RFC6125]). The securely configured URI provides the authorization statement and the server's authenticated identity confirms it is the authorized server. Method 2) If the previous check fails or is not applicable, or if the EST server's URI was made available to the client in an insecure fashion, then the EST server certificate MUST contain the id-kp-cmcRA [CMC RFC5272bis] extended key usage extension. The client MUST further verify the server's authorization by checking that the [RFC5280]-defined certificate policy extension sequence contains the 'RA Authorization' policy OID. The RA Authorization policy OID is defined as: id-cmc [[EDNOTE: TBD, perhaps 35]]. The RA Authorization policy information MUST NOT contain any optional qualifiers. Method 3) If fallback logic was invoked to accept the certificate manually, then that authentication implies authorization of the EST server. 4.2. Client Authorization When the EST server receives a CMC Simple PKI Request or rekey/renew message, the decision to issue a certificates is always a matter of local policy. Thus the CA can use any data it wishes in making that determination. The EST protocol exchange provides the EST server access to the TLS client certificate in addition to any HTTP user authentication credentials to help in that determination. The communication channel between the TLS server implementation and the EST software implementation is out-of-scope of this document. If the client authentication is incomplete (for example if the client certificate is self-signed or issued by an unknown PKI or if the client offered an unknown username/password during HTTP authentication) the server MUST extract the certificate request for manual authorization by the administrator. 4.3. Distribution of CA certificates The EST Client MAY request trust anchor information of the CA (in the form of certificates) by sending an HTTPS GET message to the EST server with an operations path of "/CACerts". Clients SHOULD request an up-to-date response before stored information has expired in order to maintain continuity of trust. Pritikin, et al. Expires January 11, 2013 [Page 20] Internet-Draft EST July 2012 The EST server SHOULD NOT require client authentication or authorization to reply to this request. The client MUST authenticate the EST server as specified in Section 3.3.1 and check the server's authorization as given in Section 4.1. If the TLS authentication and authorization is not successful then the client MAY continue the TLS handshake to completion and proceed with the /CACerts request. If the EST client continues with an unauthenticated connection the EST client MUST extract the CA certificate from the response (Section 4.3.1) and engage the end-user to authorize the CA certificate using out-of-band pre-configuration data such as a CA certificate "fingerprint" (e.g., a SHA-1, SHA-256, SHA-512, or MD5 hash on the whole CA certificate). In this case it is incumbent on the end user to properly verify the fingerprint or to provide valid out-of-band data necessary to verify the fingerprint. 4.3.1. Distribution of CA certificates response The EST server MUST respond to the client HTTPS GET message with CA trust anchor information, in the form of certificates within the CMC Simple PKI Response. The response is conveyed within an HTTP response. The EST server MUST include the current CA certificate in the response. The EST server MUST include any additional certificates the client would need to build a chain to the root certificate. For example if the EST server is configured to use a subordinate CA when signing new client requests then the appropriate subordinate CA certificates to chain to the root must be included in the response. Additional certificates MAY be included. If support for the CMP root certificate update mechanism is provided by the CA then the server MUST include the three "Root CA Key Update" certificates OldWithOld, OldWithNew, and NewWithOld. These are defined in Section 4.4 of CMP [RFC4210]. The client can always find the current self-signed CA certificate by examining the certificates received. The NewWithNew certificate is self-signed and has the latest NotAfter date. The NewWithNew certificate is the certificate that is extracted and authorized using out-of-band information as described in Section 4.3. When out-of-band validation occurs each of the other three certificates MUST be validated using normal [RFC5280] certificate path validation (using the NewWithNew certificate as the trust anchor) before they can be used to build certificate paths during peer certificate validation. Pritikin, et al. Expires January 11, 2013 [Page 21] Internet-Draft EST July 2012 The response format is the CMC Simple PKI Response as defined in [RFC5272]. The HTTP content-type of "application/pkcs7-mime" MUST be specified. The CMC Simple PKI response is Base64 encoded and sandwiched between PEM headers: -----BEGIN PKCS7----- MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh Simplified example of Base64 encoding of CMC Simple PKI Response ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD 8J4OhHvLh1o= -----END PKCS7----- 4.4. Simple Enrollment of Clients The EST client MAY request a certificate from the EST server by HTTPS POSTing using the operation path value of "/simpleEnroll". When HTTPS POSTing to the 'SimpleEnroll' location the client MUST include a CMC Simple PKI Request as specified in CMC Section 3.1 (i.e., a PKCS#10 Certification Request). Consistent with [RFC6403] the certification request "signature MUST be generated using the private key corresponding to the public key in the CertificationRequestInfo, for both signature and key establishment certification requests". The signature provides proof-of-possession of the private key to the EST server. The HTTP content-type of "application/pkcs10" MUST be specified. The format of the request is as specified in Section 6.4 of [RFC4945]. The server MUST check client authorization as specified in Section 4.2. The EST server MUST check the tls-unique value as described in Section 3.5 but depending on policy MAY accept a request without the encoded tls-unique value. The EST server applies whatever authorization or policy logic it chooses in determining if the certificate should be issued. The optional client signature certificate MAY be an existing certificate issued by the CA the EST server is providing services for or it MAY be from any other PKI the EST server indicated as acceptable during the TLS handshake. The client MAY request an additional certificate even when using an existing certificate in the TLS client authentication. For example the client can use an existing signature certificate to request a key encryption certificate. The client MUST authenticate the EST server as specified in Section 3.3.1.1. Pritikin, et al. Expires January 11, 2013 [Page 22] Internet-Draft EST July 2012 4.4.1. Simple Re-Enrollment of Clients The EST client MAY request renew/rekey of its certificate from the EST server by HTTPS POSTing using the operation path value of "/simpleReEnroll'. The certificate request is the same format as for the "simpleEnroll" path extension with the same HTTP content-type. The server MUST check client authorization as specified in Section 4.2. The EST server MUST check the tls-unique value as described in Section 3.5 but depending on policy MAY accept a request without the encoded tls-unique value. The server applies whatever authorization or policy logic it chooses in determining if the certificate should be renewed/rekeyed. The optional client signature certificate MAY be an existing certificate issued by the CA the EST server is providing services for or it MAY be from any other PKI the EST server indicated as acceptable during the TLS handshake. When attempting to renew or rekey the client SHOULD use an existing certificate for TLS client authentication (Section 3.3.1.2). The certificate being re-enrolled MAY be different than the certificate used for EST client authentication. The EST server MUST handle enrollment requests submitted to the "simpleReEnroll" URI as a renewal or rekey request. (This explicit method of indicating a re-enroll request is an alternative to the /fullCMC method specified in Section 2 of [RFC5272] wherein the "renewal and rekey requests look the same as any certification request, except that the identity proof is supplied by existing certificates from a trusted CA"). The request Subject/SubjectAltName field(s) MUST contain the identity of the certificate being re-enrolled. The ChangeSubjectName attribute, as defined in [RFC6402] MAY be included in the certificate request. The EST server MUST verify that that authenticated client is authorized to perform the inferred re-enroll operation. If the public key information in the certification request is the same as the currently issued certificate the EST server performs a renew operation. If the public key information is different than the currently issued certificate then the EST server performs a rekey operation. The specifics of these operations are out of scope of this profile. The client MUST authenticate the EST server as specified in Section 3.3.1.1. The EST client is RECOMMENDED to have obtained the current CA certificates using Section 4.3 to ensure it can validate the EST server certificate. Pritikin, et al. Expires January 11, 2013 [Page 23] Internet-Draft EST July 2012 4.4.2. Simple Enroll and Re-Enroll Response If the enrollment is successful the server response MUST have an HTTP 200 response code with a content-type of "application/pkcs7-mime". The response data is a degenerate certs- only CMC Simple PKI Response containing only the certificate issued. The CMC Simple PKI response is Base64 encoded and sandwiched between PEM headers: -----BEGIN PKCS7----- MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh Simplified example of Base64 encoding of CMC Simple PKI Response ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD 8J4OhHvLh1o= -----END PKCS7----- When rejecting a request the server MUST specify either an HTTP 4xx/ 401 error, or an HTTP 5xx error. A CMC PKI Response with an HTTP content-type of "application/pkcs7-mime" MAY be included in the response data for any error response. If the content-type is not set the response data MUST be a plain text human-readable error message. A client MAY elect not to parse a CMC error response in favor of a generic error message. If the server responds with an HTTP 202 this indicates that the request has been accepted for processing but that a response is not yet available. The server MUST include a Retry-After header as defined for HTTP 503 responses and MAY include informative human- readable content. The client MUST wait at least the specified 'retry-after' time before repeating the same request. The client repeats the initial enrollment request after the appropriate 'retry- after' interval has expired. The client SHOULD log or inform the end user of this event. The server is responsible for maintaining all state necessary to recognize and handle retry operations as the client is stateless in this regard (it simply sends the same request repeatedly until it receives a different response code). All other return codes are handled as specified in HTTP. If the EST client has not obtained the current CA certificates using Section 4.3 then it may not be able to validate the certificate received. 4.5. Full CMC The EST client MAY request a certificate from the EST server by HTTPS POSTing using the operation path value of "/fullCMC". The client MUST authenticate the server as specified in Server Pritikin, et al. Expires January 11, 2013 [Page 24] Internet-Draft EST July 2012 Authentication (Section 3.3.1.1), if method 3 is used, then the Publish Trust Anchors control within the HTTP content must be accepted manually as noted in Section 4.3. While use of TLS is not optional within EST, since a full CMC message inately provides security, a TLS NULL cipher suite may be used while making this request. The server SHOULD authenticate the client as specified in Section 3.3.1. The server MAY depend on CMC client authentication methods instead. 4.5.1. Full CMC Request When HTTPS POSTing to the "fullCMC" location the client MUST include a valid CMC message. The HTTP content-type MUST be set to "application/pkcs7-mime" as specified in [RFC5273]. 4.5.2. Full CMC Response The server responds with the client's newly issued certificate or provides an error response. If the enrollment is successful the server response MUST have an HTTP 200 response code with a content-type of "application/pkcs7-mime" as specified in [RFC5273]. The response data includes either the CMC Simple PKI Response or the CMC Full PKI Response. When rejecting a request the server MAY specify either an HTTP 4xx/ 401 error or an HTTP 5xx error. A CMC response with content-type of "application/pkcs7-mime" MUST be included in the response data for any error response. The client MUST parse the CMC response to determine the current status. All other return codes are handled as specified in Section 4.4.2 or HTTP [RFC2616]. The CMC PKI response is Base64 encoded and sandwiched between PEM headers: -----BEGIN PKCS7----- MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh Simplified example of Base64 encoding of CMC Full PKI Response ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD 8J4OhHvLh1o= -----END PKCS7----- Pritikin, et al. Expires January 11, 2013 [Page 25] Internet-Draft EST July 2012 4.6. Server-side Key Generation [[EDNOTE: This section is references [draft-ietf-pkix-cmc-serverkeygeneration-00] which has not yet been published.]] The EST client MAY request a "private" key and associated certificate from the EST server by HTTPS POSTING using the operation path value of "/serverKeyGen". The client MUST authenticate the server as specified in Section 3.3.1.1. The EST client is RECOMMENDED to have obtained the current CA certificates using Section 4.3 to ensure it can validate the EST server certificate. The EST server MUST authenticate the client as specified in Section 3.3.1. The EST server applies whatever authorization or policy logic it chooses to determine if the "private" key and certificate should be distributed. The server SHOULD use TLS-Based Client Authentication for authorization purposes. The server SHOULD respond to repeated requests from the same client with the same "private" key and certificate but MAY respond with a renewed or rekeyed "private" key and certificate. Clients that wish multiple "private" keys and certificates MUST specify a keyUsage in the certificate request which the server will use to intuit the type of key to be generated. Proper random number and key generation and storage is a server implementation responsibility. The keypair and certificate are transfered over the TLS session; the EST server MUST verify that the current ciphersuite is acceptable for securing the key data. 4.6.1. Server-side Key Generation Request The certificate request is HTTPS POSTed and is the same format as for the "/simpleEnroll" path extension with the same content-type. The public key values of the certificate request and the request signature MUST be ignored by the server. 4.6.2. Server-side Key Generation Response If the request is successful the server response MUST have an HTTP 200 response code with a content-type of "multipart/mixed" consisting of two parts. The first part is the "private" key data and the second part is the certificate data. The first submessage is an "application/pkcs8" consisting of the Pritikin, et al. Expires January 11, 2013 [Page 26] Internet-Draft EST July 2012 Base64 encoded DER-encoded PrivatekeyInfo sadwiched between the PEM headers as described in [RFC5958]: -----BEGIN PRIVATE KEY----- MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh Simplified example of Base64 encoding of DER-encoded PrivateKeyInfo ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD 8J4OhHvLh1o= -----END PRIVATE KEY----- The second submessage is an "application/pkcs7-mime" and exactly matches the certificate response to /simpleEnroll. The server response MUST use the same SubjectPublicKeyInfo as requested or the request MUST be denied. When rejecting a request the server MUST specify either an HTTP 4xx/ 401 error, or an HTTP 5xx error. If the content-type is not set the response data MUST be a plain text human-readable error message. 4.7. CSR Attributes The CA MAY want to include client-provided attributes in certificates that it issues and some of these attributes may describe information that is not available to the CA. For this reason, the EST client MAY request a set of attributes from the EST server to include in its certification request. 4.7.1. CSR Attributes Request The EST Client MAY request a list of CA-desired CSR attributes from the CA by sending an HTTPS GET message to the EST server with an operations path of "/CSRAttrs". Clients SHOULD request such a list if they have have no a priori knowledge of what attributes are desired by the CA in an enrollment request or when dictated by policy. 4.7.2. CSR Attributes Response The server MUST reply to the client's HTTPS GET message with a (set of) attribute(s). Responses to attribute request messages MUST be encoded as content type "application/csrattrs" and conveyed within an HTTP response. The syntax for application/csrattrs body is as follows: Csrattrs ::= SEQUENCE SIZE (0..MAX) OF OBJECT IDENTIFIER { } A robust application SHOULD output Distinguished Encoding Rules (DER) Pritikin, et al. Expires January 11, 2013 [Page 27] Internet-Draft EST July 2012 ([X.690]) but MAY use Basic Encoding Rules (BER) ([X.680]). Data produced by DER or BER is 8-bit. When the transport for the application/csrattrs is limited to 7-bit data, a suitable transfer encoding MUST be applied in MIME-compatible transports. The base64 encoding (section 4 of [RFC4648]) SHOULD be used with application/ csrattrs, although any 7-bit transfer encoding may work. Servers include zero or more object identifiers that they wish the client to include in their certification request. When the server encodes csrattrs as an empty SEQUENCE OF it means that the server has no attributes it wants in client certification requests. For example, if a CA wishes to have a certification request contain the MAC address [RFC2397] of a device and the pseudonym [X.520] and friendly name [RFC2925] of the holder of the private analog to the public key in the certification request, it takes the following object identifiers: o macAddress: 1.3.6.1.1.1.1.22 o pseudonym: 2.5.4.65 o friendlyName: 1.2.840.113549.1.9.20 and encodes them into an ASN.1 SEQUENCE to produce: 30 19 06 07 2b 06 01 01 01 01 16 06 03 55 04 41 06 09 2a 86 48 86 f7 0d 01 09 14 and then base64 encodes the resulting ASN.1 SEQUENCE to produce: MBkGBysGAQEBARYGA1UEQQYJKoZIhvcNAQkU The resulting response would look like this: Content-Type: application/csrattrs; name=attributes Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=attributes MBkGBysGAQEBARYGA1UEQQYJKoZIhvcNAQkU 5. IANA Considerations (This section is incomplete) The following aspects should be registered with IANA Considerations: Pritikin, et al. Expires January 11, 2013 [Page 28] Internet-Draft EST July 2012 The RA Authorization certificate policy extension OID as discussed in Section 4.1 requires registration with IANA. [[EDNOTE: The URLs specified in Section 1 probably do not need to be registered with IANA.]] IANA SHALL update the Application Media Types registry with the following filled-in template from [RFC4288]. The media subtype for Attributes in a CertificationRequest is application/csrattrs. Type name: application Subtype name: csrattrs Required parameters: None Optional parameters: None Encoding considerations: binary; Security Considerations: Clients request a list of attributes that servers wish to be in certification requests. The request/response SHOULD be done in a TLS-protected tunnel. Interoperability considerations: None Published specification: This memo. Applications which use this media type: Enrollment over Secure Transport (EST) Additional information: Magic number(s): None File extension: None Macintosh File Type Code(s): Person & email address to contact for further information: Dan Harkins Pritikin, et al. Expires January 11, 2013 [Page 29] Internet-Draft EST July 2012 Restrictions on usage: None Author: Dan Harkins Intended usage: COMMON Change controller: The IESG 6. Security Considerations (This section is incomplete) "Badges? We ain't got no badges. We don't need no badges! I don't have to show you any stinkin' badges!" -- The Treasure of the Sierra Madre. As described in CMC Section 6.7, "For keys that can be used as signature keys, signing the certification request with the private key serves as a POP on that key pair". The inclusion of tls-unique within the certification request links the the proof-of-possession to the TLS proof-of-identity. As given in Section 3.3.1.2 clients use an existing certificate for TLS client authentication. If a certificate with appropriate key usage is not available the client MAY generate one. If a self-signed certificate with appropriate key usage is used the server SHOULD require HTTP-based client authentication according to server policy as described in Section 3.3.1.2 and Section 4.2. The server MAY fallback on manual authorization by the server administrator. Clients authenticate EST servers by means of TLS authentication. If a client does not possess a root certificate suitable for validating an EST server certificate, it MAY rely upon other trusted root certificates it has (such as those found in its HTTPS store). The client then is able to retrieve additional root certificates as given in Section 4.3. Alternatively, a server certificate MAY be authenticated manually as specified in Section 3.3.1.1 #3. As noted in Section 3.3.1.1 servers use an existing certificate for TLS server authentication. When the server certificate is issued by a mutually trusted PKI hierarchy, validation proceeds as specified in Section 4.1. In this situation the client has validated the server as being a valid responder for the URI configured but can not directly verify that the responder is authorized as an RA within the to-be-enrolled PKI hierarchy. A client may thus be enticed to expose username/password or certificate enrollment requests to an unauthorized server (if the server presents a valid HTTPS certificate Pritikin, et al. Expires January 11, 2013 [Page 30] Internet-Draft EST July 2012 for an erroneous URL that the client has been tricked into using). Proof-of-identity and Proof-of-possession checks by the CA prevent an illegitimate RA from leveraging such misconfigured clients to act as a man-in-the-middle during client authenticated operations but it is possible for such illegitimate RAs to send the client doctored messages or erroneous CA certificate lists. If the illegitimate RA has successfully phished a username/password or PIN from the client it might try to use these values to enroll its own keypair with the real PKI hierarchy. EST servers identified with an externally issued server certificate SHOULD require HTTPS-based client authentication (Section 3.3.1.2). Similarly EST clients SHOULD use an existing client certificate to identify themselves and otherwise prevent "private data" (obviously including passwords but also including private identity information) from being exposed during the enrollment exchange a weak server authorization method is used. Section 3.2.3 allows clients to optionally authenticate using HTTP- based authentication in place of TLS-based authentication. HTTP- based authentication MUST NOT take place unless performed over a TLS- protected link. The server-side key generation method allows keys to be transported over the TLS connection to the client. The distribution of "private" key material is inherently risky and servers are NOT RECOMMENDED to support this operation by default. Clients are NOT RECOMMENDED to request this service unless there is a compelling operational benefit such as the use of [BGPsec RPKI]. Regarding the CSR attributes that the CA may list for inclusion in an enrollment request, there are no real inherent security issues with the content being conveyed but an adversary who is able to interpose herself into the conversation could exclude attributes that a server may want, include attributes that a server may not want, and render meaningless other attributes that a server may want. [[EDNOTE: need final reference for BGPsec RPKI]] Support for Basic authentication as specified in HTTP [RFC2617] allows the server access to the client's cleartext password. This provides integration with legacy username/password databases but requires exposing the plaintext password to the EST server. Use of a PIN or one-time-password can help mitigate concerns but EST clients are RECOMMENDED to use such credentials only once to obtain an appropriate client certificate to be used during future interactions with the EST server. 7. References Pritikin, et al. Expires January 11, 2013 [Page 31] Internet-Draft EST July 2012 7.1. Normative References [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key Infrastructure Operational Protocols: FTP and HTTP", RFC 2585, May 1999. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A., and L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification Request Syntax Specification Version 1.7", RFC 2986, November 2000. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, "Internet X.509 Public Key Infrastructure Certificate Management Protocol (CMP)", RFC 4210, September 2005. [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and Registration Procedures", BCP 13, RFC 4288, December 2005. [RFC4346] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.1", RFC 4346, April 2006. [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, October 2006. [RFC4945] Korver, B., "The Internet IP Security PKI Profile of IKEv1/ISAKMP, IKEv2, and PKIX", RFC 4945, August 2007. Pritikin, et al. Expires January 11, 2013 [Page 32] Internet-Draft EST July 2012 [RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS (CMC)", RFC 5272, June 2008. [RFC5273] Schaad, J. and M. Myers, "Certificate Management over CMS (CMC): Transport Protocols", RFC 5273, June 2008. [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, May 2008. [RFC5746] Rescorla, E., Ray, M., Dispensa, S., and N. Oskov, "Transport Layer Security (TLS) Renegotiation Indication Extension", RFC 5746, February 2010. [RFC5929] Altman, J., Williams, N., and L. Zhu, "Channel Bindings for TLS", RFC 5929, July 2010. [RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958, August 2010. [RFC5967] Turner, S., "The application/pkcs10 Media Type", RFC 5967, August 2010. [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)", RFC 6125, March 2011. [RFC6402] Schaad, J., "Certificate Management over CMS (CMC) Updates", RFC 6402, November 2011. [X.680] ITU-T Recommendation, "ITU-T Recommendation X.680 Abstract Syntax Notation One (ASN.1): Specification of basic notation", November 2008, . [X.690] ITU-T Recommendation, "ITU-T Recommendation X.690 ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", November 2008, . 7.2. Informative References [IDevID] IEEE Std, "IEEE 802.1AR Secure Device Identifier", December 2009, . [RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397, August 1998. [RFC2925] White, K., "Definitions of Managed Objects for Remote Ping, Traceroute, and Lookup Operations", RFC 2925, September 2000. [RFC6403] Zieglar, L., Turner, S., and M. Peck, "Suite B Profile of Certificate Management over CMS", RFC 6403, November 2011. [X.520] ITU-T Recommendation, "ITU-T Recommendation X.520 The Directory: Selected attribute types", November 2008, . Appendix A. Server Discovery (informative) Clients can use DNS-SD or similar discovery algorithms to determine the EST server URI. In such cases it is expected that method 2 (Section 3.3.1.1) be used during server authentication because the first method is insecure if the discovery mechanism is insecure. If the user interaction in the third method is acceptable it is expected that the user would also supply the URI instead of using a discovery protocol. Appendix B. External TLS concentrator (informative) In some deployments it may be beneficial to use a TLS concentrator to offload the TLS processing from the server. The TLS server should not reject the connection based on PKIX validation of the client certificate. Instead the client certificate is passed to the EST server layer for verification and authorization. This allows support of external TLS concentrators that might provide an independent TLS implementation. The TLS concentrator does validate the TLS Section 7.4.8 'Certificate Verify'. In such a deployment the TLS client authentication result must be Pritikin, et al. Expires January 11, 2013 [Page 34] Internet-Draft EST July 2012 forwarded to the EST server layer. For example a TLS concentrator might insert the client certificate into the HTTP header (first removing any existing client certificates, possibly inserted by a nefarious client, from the HTTP headers) before forwarding the HTTP connection to the EST server. The EST server MUST be specifically configured by the administrator to accept this mechanism. Appendix C. CGI Server implementation (informative) In some deployments it may be beneficial to use a HTTPS server that runs the EST server as a CGI application. The HTTPS server should not reject the connection based on PKIX validation of the client certificate. Instead the client certificate is passed to the EST server layer for verification and authorization. This allows support of external HTTPS servers that might provide an independent TLS implementation. In such a deployment the TLS client authentication result must be forwarded to the EST server layer. For example an HTTPS server might insert the client certificate into the environment variables before forwarding the HTTP data to the EST server. Appendix D. Operational Scenario Example Messages (informative) This section expands on the Operational Scenario Overviews by providing detailed examples of the messages at each TLS layer. Figures are informative sections of TLSv1 D.1. Obtaining CA Certificates The following is an example of a valid /CACerts exchange. During the intial TLS handshake the client can ignore the optional server generated "certificate request" and can instead proceed with the HTTP GET request: Pritikin, et al. Expires January 11, 2013 [Page 35] Internet-Draft EST July 2012 GET /CACerts HTTP/1.1 User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS SL/0.9.8b zlib/1.2.3 libidn/0.6.5 Host: 127.0.0.1:8085 Accept: */* In response the server provides the current CA certificate: <= Recv header, 38 bytes (0x26) Content-Type: application/pkcs7-mime == Info: no chunk, no close, no size. Assume close to signal end <= Recv header, 2 bytes (0x2) <= Recv data, 1111 bytes (0x457) -----BEGIN PKCS7-----.MIIDEQYJKoZIhvcNAQcCoIIDAjCCAv4CAQExADALBg kqhkiG9w0BBwGgggLkMIIC.4DCCAcigAwIBAgIJAOjxMZcXhE5wMA0GCSqGSIb3D QEBBQUAMBcxFTATBgNVBAMT.DGVzdEV4YW1wbGVDQTAeFw0xMjA3MDQxODM5Mjda Fw0xMzA3MDQxODM5MjdaMBcx.FTATBgNVBAMTDGVzdEV4YW1wbGVDQTCCASIwDQY JKoZIhvcNAQEBBQADggEPADCC.AQoCggEBALQ7SjZSt6qrnBzUnBNj9z4oxYkvMA Vh0OIOVRkNhz/2kDGsds0ne7cw.W33kYlxPba4psdLMixCT/O8ZQMpgA+QFKtwb9 VPE8EFUgGzxSYHQHjhJsbg0BVaN.Ya38vjKMjvosuSXUHwkvU57SInSkMr3/aNtS T8qFfeC6Vuf/G/GLHGuHQKAy/DSo.206MjaMNmWYRVQQVErGookRA4GBF/YE+G/C SlTsCQNE0KyBFz8JWIkgYY2gYkxb7.wWMvvhaU/Esp+2DG92v9Dhs2MRgrR+WPs7 Y6CYOLD5Mr5lEdkHg27IxkSAoRrI6D.fnVVEQGCj7QrrsUgfXFVYv6cCWFfhMcCA wEAAaMvMC0wDAYDVR0TBAUwAwEB/zAd.BgNVHQ4EFgQUhH9KxW5TsjkgL7kg2kxJ yy5tD/MwDQYJKoZIhvcNAQEFBQADggEB.AD+vydZo292XFb2vXojdKD57Gv4tKVm hvXRdVInntzkY/0AyFCfHJ4BwndgtMh4t.rvBD8+8dL+W3jfPjcSCcUQ/JEnFuMn b5+kivLeqOnUshETasFPBz2Xq4C1sHDno9.CWOcsjPPw08Tn4dSrzDBSq1NdXB2z 9NOpaVnbpb01qQGhXSOaEvcbZcDuGiW7Di3.gV++remokuPph/s6XoZffzc7ZVzf Job6tS4RwNz01sutPybXiRWivOz7+QeCOT87.nTGlkQH/+RImUyJ2jefjAW/GDFT Pzek6cZnabAtsg32n0Pv0j0/1RTNSdYGxPIVA.2f9fhMqMz+vm3w4CFNkGZnOhAD EA.-----END PKCS7-----. D.2. Previously Installed Signature Certificate The following is an example of a valid /simpleEnroll exchange. During this exchange the EST client uses an existing certificate issued by a trusted 3rd party PKI to obtain an initial certificate from the EST server. During the initial TLS handshake the server generated "certificate request" includes both the distinguished name of the CA the EST server provides services for ("estExampleCA") and it includes the distinguished name of a trusted 3rd party CA ("estEXTERNALCA"): Pritikin, et al. Expires January 11, 2013 [Page 36] Internet-Draft EST July 2012 0d 00 00 3d 03 01 02 40 00 37 00 1a 30 18 31 16 ...=...@.7..0.1. 30 14 06 03 55 04 03 13 0d 65 73 74 45 58 54 45 0...U....estEXTE 52 4e 41 4c 43 41 00 19 30 17 31 15 30 13 06 03 RNALCA..0.1.0... 55 04 03 13 0c 65 73 74 45 78 61 6d 70 6c 65 43 U....estExampleC 41 A Which decodes as: Acceptable client certificate CA names /CN=estEXTERNALCA /CN=estExampleCA The EST client provides a certificate issued by "estEXTERNALCA" in the certificate response and the TLS handshake proceeds to completion. The EST server accepts the EST client certificate for authentication and accepts the EST client's POSTed certificate request: POST /simpleEnroll HTTP/1.1 User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS SL/0.9.8b zlib/1.2.3 libidn/0.6.5 Host: 127.0.0.1:8085 Accept: */* Content-Type: application/x-est-pkcs10 Content-Length: 952 => Send data, 952 bytes (0x3b8) -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgNjEYMBYGA1UEBRMPUElEOld pZGdldCBTTjo2MIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAwhYyI+ aYezyx+kW0GVUbMKLf2BUd8BgGykkIJYxms6SH.Bv5S4ktcpYbEpR9iCmp96vK6a Ar57ArZtMmi0Y6eLX4c+njJnYhUeTivnfyfMM5d.hNVwyzKbJagm5f+RLTMfp0y0 ykqrfZ1hFhcNrRzF6mJeaORTHBehMdu8RXcbmy5R.s+vjnUC4Fe3/oLHtXePyYv1 qqlkk0XDrw/+lx0y4Px5tiyb84iPnQOXjG2tuStM+.iEvfpNAnwU0+3GDjl3sjx0 +gTKvblp6Diw9NSaqIAKupcgWsA0JlyYkgPiJnXFKL.vy6rXoOyx3wAbGKLrKCxT l+RH3oNXf3UCH70aD758QIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBADwpafWU BsOJ2g2oyHQ7Ksw6MwvimjhB7GhjweCcceTSLInUMk10.4E0TfNqaWcoQengMVZr IcbOb+sa69BWNB/WYIULfEtJIV23/g3n/y3JltMNw/q+R.200t0bNAViijHQHmlF 6dt93tkRrTzXnhV70Ijnff08G7P9HfnXQH4Eiv3zOB6Pak.JoL7QlWQ+w5vHpPo6 WGH5n2iE+Ql76F0HykGeqaR402+ae0WlGLHEvcN9wiFQVKh.KUHteU10SEPijlqf QW+hciLleX2CwuZY5MqKb4qqyDTs4HSQCBCl8jR2cXsGDuN4.PcMPp+9A1/UPuGD jhwPt/K3y6aV8zUEh8Ws=.-----END CERTIFICATE REQUEST-----. The EST server uses the trusted 3rd party CA issued certificate to perform additional authorization and issues a certificate to the client: Pritikin, et al. Expires January 11, 2013 [Page 37] Internet-Draft EST July 2012 <= Recv header, 38 bytes (0x26) Content-Type: application/pkcs7-mime == Info: no chunk, no close, no size. Assume close to signal end <= Recv header, 2 bytes (0x2) <= Recv data, 1200 bytes (0x4b0) -----BEGIN PKCS7-----.MIIDUQYJKoZIhvcNAQcCoIIDQjCCAz4CAQExADALBg kqhkiG9w0BBwGgggMkMIID.IDCCAgigAwIBAgIBBjANBgkqhkiG9w0BAQUFADAXM RUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM3WhcNMTMwNzA0 MTgzOTM3WjBBMSUwIwYDVQQD.ExxyZXEgYnkgY2xpZW50IGluIGRlbW8gc3RlcCA 2MRgwFgYDVQQFEw9QSUQ6V2lk.Z2V0IFNOOjYwggEiMA0GCSqGSIb3DQEBAQUAA4 IBDwAwggEKAoIBAQDCFjIj5ph7.PLH6RbQZVRswot/YFR3wGAbKSQgljGazpIcG/ lLiS1ylhsSlH2IKan3q8rpoCvns.Ctm0yaLRjp4tfhz6eMmdiFR5OK+d/J8wzl2E 1XDLMpslqCbl/5EtMx+nTLTKSqt9.nWEWFw2tHMXqYl5o5FMcF6Ex27xFdxubLlG z6+OdQLgV7f+gse1d4/Ji/WqqWSTR.cOvD/6XHTLg/Hm2LJvziI+dA5eMba25K0z 6IS9+k0CfBTT7cYOOXeyPHT6BMq9uW.noOLD01JqogAq6lyBawDQmXJiSA+ImdcU ou/Lqteg7LHfABsYousoLFOX5Efeg1d./dQIfvRoPvnxAgMBAAGjTTBLMAkGA1Ud EwQCMAAwHQYDVR0OBBYEFJv4oLLeNxNK.OMmQDDujyNR+zaVPMB8GA1UdIwQYMBa AFIR/SsVuU7I5IC+5INpMScsubQ/zMA0G.CSqGSIb3DQEBBQUAA4IBAQCMdomfdR 9vi4VUYdF+eym7F8qVUG/1jtjfaxmrzKeZ.7LQ1F758RtwG9CDu2GPHNPjjeM+DJ RQZN999eLs3Qd/DIJCNimaqdDqmkeBFC5hq.LZOxbKhSmhlR7YKjIZuyI299rOaI W54ULyz8k0zw6R1/0lMJTsDFGJM+9yDeaARE.n3vtKnUDGHsVU3fYpDENaqUunoU MZfuEdejfHhU7lVbJI1oSJbnRwBFkPr/RQ3/5.FymcrBD9RpAM5MsQIn0BONil/o JM+LjOJqyZLbBxz6P3w/OiJGYJNfFT8YudLfjZ.LDX8A8FFcReapNELC4QxE4OrA hN3sQUT2O7ndIsit4kJoQAxAA==.-----END PKCS7-----. D.3. Username/Password Distributed Out-of-Band The following is an example of a valid /simpleEnroll exchange. During this exchange the EST client uses an out-of-band distributed username/password to authenticate itself to the EST server. During the intial TLS handshake the client can ignore the optional server generated "certificate request" and can instead proceed with the HTTP POST request: Pritikin, et al. Expires January 11, 2013 [Page 38] Internet-Draft EST July 2012 POST /simpleEnroll HTTP/1.1 User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS SL/0.9.8b zlib/1.2.3 libidn/0.6.5 Host: 127.0.0.1:8085 Accept: */* Content-Type: application/x-est-pkcs10 Content-Length: 952 => Send data, 952 bytes (0x3b8) -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgMjEYMBYGA1UEBRMPUElEOld pZGdldCBTTjoyMIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAz9lXz9 MowulOx0W5v1k7GKlsNy7mAgmkz/wZDImBDXez.QZCb8lrO8iTD3tI0NH2xpkY3b uqFjdtQTzCmANLyNWtR1sC5GjN/EM1JSCrO/zZM.ig835RXJTP878N/jNW7EzSxb /zK5OzKJoRbZ4HgZm4NDapMfMcB4jqBdPxoPAqeR.+KTkv1+9m1vvsdKIs5Hm4Sp O2WolHPw5BCXdu5zleb6ACih7Zpd2cpHFz6ZHC0G1.Of+F//0BzkFSqWsmUomyJy WCfLCuX9grs1CNlLxw0gcMprdTxLxjc18z03ZmBCq0.qq5/mUK/tv9R2k8+WuP3a kzTUIkeHtcp6FVFl3D+TwIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBAJH7Etuy B/oQgQeals08mD2U31FfQ/uYqjNxzZpZJSzVLGMASv9a.pNzaWdfqPdIs+ZZ+gAQ QkVcXjdbqY3pAf/EeWk+KnuAUjOIPKu3ZBPVbWbXu/Ie7.F1ekQ7TLkFNkHSxHRu 2/bPIByBLRVfWNVXd3wPq+QxqMqgIjBGaTJM5kuHndYFGj.Xdf4rlGRPyOOwG/Xf QrKBB3tzpbJCy+cwOUAJFPOTO+86RUjf9Wh+yoM182vlg8O.FyEaaA/PMpl3aEcT BlRZmPx4e7FLwGIhbgE7/6K0nF99xdGd7JYPHasbcWszxD0Z.oPYm+44g0gOnhlj OWpRiKXcnngSSutRILaw=.-----END CERTIFICATE REQUEST-----. == Info: upload completely sent off: 952 out of 952 bytes == Info: HTTP 1.1 or later with persistent connection, pipelining supported The EST server accepts this request but since a client certificate was not provided for authentication/authorization the EST server responds with the WWW-authenticate header: <= Recv header, 27 bytes (0x1b) HTTP/1.1 401 Unauthorized <= Recv header, 75 bytes (0x4b) WWW-Authenticate: Digest qop="auth", realm="estrealm", nonce="13 41427174" The EST client repeats the request, this time including the requested Authorization header: Pritikin, et al. Expires January 11, 2013 [Page 39] Internet-Draft EST July 2012 == Info: SSL connection using AES256-SHA == Info: Server certificate: == Info: subject: CN=127.0.0.1 == Info: start date: 2012-07-04 18:39:27 GMT == Info: expire date: 2013-07-04 18:39:27 GMT == Info: common name: 127.0.0.1 (matched) == Info: issuer: CN=estExampleCA == Info: SSL certificate verify ok. == Info: Server auth using Digest with user 'estuser' => Send header, 416 bytes (0x1a0) POST /simpleEnroll HTTP/1.1 Authorization: Digest username="estuser", realm="estrealm", nonc e="1341427174", uri="/simpleEnroll", cnonce="ODc0OTk2", nc=00000 001, qop="auth", response="48a2b671ccb6596adfef039e134b7d5d" User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS SL/0.9.8b zlib/1.2.3 libidn/0.6.5 Host: 127.0.0.1:8085 Accept: */* Content-Type: application/x-est-pkcs10 Content-Length: 952 => Send data, 952 bytes (0x3b8) -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgMjEYMBYGA1UEBRMPUElEOld pZGdldCBTTjoyMIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAz9lXz9 MowulOx0W5v1k7GKlsNy7mAgmkz/wZDImBDXez.QZCb8lrO8iTD3tI0NH2xpkY3b uqFjdtQTzCmANLyNWtR1sC5GjN/EM1JSCrO/zZM.ig835RXJTP878N/jNW7EzSxb /zK5OzKJoRbZ4HgZm4NDapMfMcB4jqBdPxoPAqeR.+KTkv1+9m1vvsdKIs5Hm4Sp O2WolHPw5BCXdu5zleb6ACih7Zpd2cpHFz6ZHC0G1.Of+F//0BzkFSqWsmUomyJy WCfLCuX9grs1CNlLxw0gcMprdTxLxjc18z03ZmBCq0.qq5/mUK/tv9R2k8+WuP3a kzTUIkeHtcp6FVFl3D+TwIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBAJH7Etuy B/oQgQeals08mD2U31FfQ/uYqjNxzZpZJSzVLGMASv9a.pNzaWdfqPdIs+ZZ+gAQ QkVcXjdbqY3pAf/EeWk+KnuAUjOIPKu3ZBPVbWbXu/Ie7.F1ekQ7TLkFNkHSxHRu 2/bPIByBLRVfWNVXd3wPq+QxqMqgIjBGaTJM5kuHndYFGj.Xdf4rlGRPyOOwG/Xf QrKBB3tzpbJCy+cwOUAJFPOTO+86RUjf9Wh+yoM182vlg8O.FyEaaA/PMpl3aEcT BlRZmPx4e7FLwGIhbgE7/6K0nF99xdGd7JYPHasbcWszxD0Z.oPYm+44g0gOnhlj OWpRiKXcnngSSutRILaw=.-----END CERTIFICATE REQUEST-----. The ESTserver uses the username/password to perform authentication/ authorization and responds with the issued certificate: Pritikin, et al. Expires January 11, 2013 [Page 40] Internet-Draft EST July 2012 <= Recv header, 38 bytes (0x26) 0000: Content-Type: application/pkcs7-mime == Info: no chunk, no close, no size. Assume close to signal end <= Recv header, 2 bytes (0x2) <= Recv data, 1200 bytes (0x4b0) -----BEGIN PKCS7-----.MIIDUQYJKoZIhvcNAQcCoIIDQjCCAz4CAQExADALBg kqhkiG9w0BBwGgggMkMIID.IDCCAgigAwIBAgIBAjANBgkqhkiG9w0BAQUFADAXM RUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM0WhcNMTMwNzA0 MTgzOTM0WjBBMSUwIwYDVQQD.ExxyZXEgYnkgY2xpZW50IGluIGRlbW8gc3RlcCA yMRgwFgYDVQQFEw9QSUQ6V2lk.Z2V0IFNOOjIwggEiMA0GCSqGSIb3DQEBAQUAA4 IBDwAwggEKAoIBAQDP2VfP0yjC.6U7HRbm/WTsYqWw3LuYCCaTP/BkMiYENd7NBk JvyWs7yJMPe0jQ0fbGmRjdu6oWN.21BPMKYA0vI1a1HWwLkaM38QzUlIKs7/NkyK DzflFclM/zvw3+M1bsTNLFv/Mrk7.MomhFtngeBmbg0Nqkx8xwHiOoF0/Gg8Cp5H 4pOS/X72bW++x0oizkebhKk7ZaiUc./DkEJd27nOV5voAKKHtml3ZykcXPpkcLQb U5/4X//QHOQVKpayZSibInJYJ8sK5f.2CuzUI2UvHDSBwymt1PEvGNzXzPTdmYEK rSqrn+ZQr+2/1HaTz5a4/dqTNNQiR4e.1ynoVUWXcP5PAgMBAAGjTTBLMAkGA1Ud EwQCMAAwHQYDVR0OBBYEFChDQpKEfG9c.e4JaMf8438tb2XOIMB8GA1UdIwQYMBa AFIR/SsVuU7I5IC+5INpMScsubQ/zMA0G.CSqGSIb3DQEBBQUAA4IBAQAn42mIVG piaY4yqFD0F8KyUhKsdNnyKeeISQxP//lp.quIieJzdWSc7bhWZNldSzNswCod8B 4eJToQejLSNb8JBDC849z0tcuyHgN6N/p8z.IwI+hAlfXS9q02OECyFes4Jmzc7r erE5jtOdGsEDBIscw/A+Kv86wv6BKbagMslQ.51AJyPsL6iBhm7LPFrErJgH2kWN jDKFH9CcVFjXvgriMrLPFeqQWOpj/2XF+4m+c.f9QP5tSjieHJR1hnYk2tlodfE7 iV4pJ07Mmf3yBf753VSUVybqWiMCd0Lm7oghSX.E2GAxrsU1N+N1odn+gJ2wmxTu AC2aHt9VPRViov4RRTvoQAxAA==.-----END PKCS7-----. D.4. Re-Enrollment The following is an example of a valid /simpleReEnroll exchange. During this exchange the EST client authenticates itself using an existing certificate issued by the CA the EST server provides services for. Initially this exchange is identical to enrollment using an externally issued certificate for client authentication since the server is not yet aware of the client's intention. As in that example the EST server the server generated "certificate request" includes both the distinguished name of the CA the EST server provides services for ("estExampleCA") and it includes the distinguished name of a trusted 3rd party CA ("estEXTERNALCA"). Pritikin, et al. Expires January 11, 2013 [Page 41] Internet-Draft EST July 2012 0d 00 00 3d 03 01 02 40 00 37 00 1a 30 18 31 16 ...=...@.7..0.1. 30 14 06 03 55 04 03 13 0d 65 73 74 45 58 54 45 0...U....estEXTE 52 4e 41 4c 43 41 00 19 30 17 31 15 30 13 06 03 RNALCA..0.1.0... 55 04 03 13 0c 65 73 74 45 78 61 6d 70 6c 65 43 U....estExampleC 41 A In text format this is: Acceptable client certificate CA names /CN=estEXTERNALCA /CN=estExampleCA The EST client provides a certificate issued by "estExampleCA" in the certificate response and the TLS handshake proceeds to completion. The EST server accepts the EST client certificate for authentication and accepts the EST client's POSTed certificate request. The rest of the protocol traffic is effectively identical to a normal enrollment. D.5. Server Key Generation The following is an example of a valid /serverKeyGen exchange. During this exchange the EST client authenticates itself using an existing certificate issued by the CA the EST server provides services for. The initial TLS handshake is identical to the enrollment example handshake. The HTTP POSTed message is: Pritikin, et al. Expires January 11, 2013 [Page 42] Internet-Draft EST July 2012 POST /serverKeyGen HTTP/1.1 User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS SL/0.9.8b zlib/1.2.3 libidn/0.6.5 Host: 127.0.0.1:8085 Accept: */* Content-Type: application/x-est-pkcs10 Content-Length: 968 => Send data, 968 bytes (0x3c8) -----BEGIN CERTIFICATE REQUEST-----.MIICkzCCAXsCAQAwTjEyMDAGA1UE AxMpc2VydmVyS2V5R2VuIHJlcSBieSBjbGll.bnQgaW4gZGVtbyBzdGVwIDUxGDA WBgNVBAUTD1BJRDpXaWRnZXQgU046NTCCASIw.DQYJKoZIhvcNAQEBBQADggEPAD CCAQoCggEBAMnlUlq0ag/fDAVhLgrXEAD6WtZw.Y2rVGev5saWirer2n0OzghB59 uJByxPo0DYBYqZRuoRF0FTL1ZZTMaZxivge0ecA.ZcoR46jwSBoceMT1jkwFyAER t9Q2EwdnJLIPo/Ib2PLJNb4Jo8NNKmxtg55BgIVi.vkIB+rMtLeYRUVL0RUaBAqX FmtXRDceVFIEY24iUQw6vESGJKpArht592aT8lyaP.24bZovuG19dd5xtTX3j37K x49SlkUvLSpD6ZavIFAZn7Yv19LBKHvRIemybUo294.QeLb/VYP1O+EAthV/igiX 1DHqlUZCZp5SdyUXUwZPatFboNwEVR0R3MJwVECAwEA.AaAAMA0GCSqGSIb3DQEB BQUAA4IBAQAqhHezK5/tvbXleHO/aTBVYO9l414NM+WA.wJcnS2UaJYScPBqlYK/ gij+dqAtFE+5ukAj56t7HnooI4EFo9r8jqCHewx7iLZYh.JDxo4hWOsAvHV+Iziy jkhJNdHBIqGM7Gd5f/2VJLEPQPmwNOL5P+2O4eQC/QeEYc.bAmfhOS8b/ZH09/9T PeaeQpjspjOui/100OuLE8KvU3FM0sXMYt1Va0A0jxzl+5k.EiEJo+ltXsQwdP0H csoTNBN+j3K18omJQS0e91X8v0xkMWYhUtonXD0YZ6SO/B9c.AE6GTADHA/xpSvA cqlWa+FHxjwEMXdmViHvMUywo31fDZ/TUvCPX.-----END CERTIFICATE REQUE ST-----. After processing the request the EST server response is: <= Recv header, 17 bytes (0x11) HTTP/1.1 200 OK <= Recv header, 16 bytes (0x10) Status: 200 OK <= Recv header, 67 bytes (0x43) Content-Type: multipart/mixed ; boundary=estServerExampleBoundar y == Info: no chunk, no close, no size. Assume close to signal end <= Recv header, 2 bytes (0x2) <= Recv data, 3234 bytes (0xca2) This is the preamble. It is to be ignored, though it.is a handy place for estServer to include an explanatory note.including con tact or support information..--estServerExampleBoundary.Content- Type=application/pkcs8..-----BEGIN PRIVATE KEY-----.MIIEvQIBADAN BgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC0781l7tri0yii.Mb9ZZYch8ze izXrjMPF/Rxoz2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSM.tzxn4l+9tI sVDkAe4FyzN0hLd/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blv.aMUKDSJhV bQ+z/G1W1TRx3iWi5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4Dx.Igbx9vG0 mftIIxM4TUX28KBbaLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8.DQiQEki nn66GPMtm1SNgitxFxWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhk.g0gMIQ Pritikin, et al. Expires January 11, 2013 [Page 43] Internet-Draft EST July 2012 TXAgMBAAECggEANlrz8XNX/lxBELixK0H83o4aYKYqDKZfZkUN8hU33xpu.Y/0sc VbLbu46WzysoIfJFyUC+zFJnbMCCOPjGbI/4NWkEqc9TAlKz+wDo+hf5bf0.ypFr EmikHk8R3fkpnvKi69ldw0iYnqcFVhq7VtGrSmJcy6Hckwbk7EBoUZGL0wtp.xlO 6XlhksAvn8+75qoWzsNhi7S/L0IVCVLbUaV3hodTHlH5M4daFbqyRWD7UiPKt.Q3 hdw1rpyVZg8ZbBFp0Ej4f9GdRaq88SIKMKCDu3t9ibn/v1kEte+PxhuwyW+d0o.h kKSEW0yLKCzQm5tujsPq0UVzPBkLJACUnFAi+a4AQKBgQDu6VLH2eYoTjPPTyAv. vOJnNWP7oMzyJ4/eFqdE9m+2Ajm/0qaMY95ftZ+GpEKggvC6Z5DFevEmgH4Sg2+G .gFd93diyRPScVbNE8SmpXxLPU2UoykVmICuQZzLDNE18B3buxAm2GJ219NEnZOe c.jPMOV/IcG1aLzTqQssL3zo/0gQKBgQDB4Olpg3EBggtJ/+dlkLHUw8c7Pe3UyL kS.VxVsyQwioYt8xMeCWuPvPNFcOjcW53KN/YSpCVjpttKGsPtLibMlKYKgasEqg cvl.Vb5OFtA/jNAP3mdAgCzBn6IF1NhVQe2dclo5puZ0gO38HDWq7EtqSi9Q0JSM g3YC.QNcOORptVwKBgQCHrCafaYWDhA11/+g2U9x6Yd56ifF43rCbnV+2EQCVaqQ i49xC.w4AH+Bs0mdlgT5unL6MOEmgZxkRR/SP7TKzixHYHnpMOqLhaQV24Wk5TQH ek92D7.wu8aXRB9vBj4g0CuDNO6/jWpm/KenXXN+Fka3ySVg4zdbVmBzJJdqYckg QKBgFXS.zSBzGgwz1/F7AaDZK49m1wPnhyeBb0OqHwbX/LI71rZ1mWef+nSF9Juh /Y77B5/J.UPdO9vgGgS00nRk0LIRP2s5OU5IQgQTVLvf8a1UmbVgI+KX511Yi5yM ztEwRcjEX.VM9ejXeXN0I57pvqG/xCOK3Kl2eYLh4TO9/E8WjjAoGAA1mqUV4Hnf 4yvF1rydMp.fpvoWekiiRE33iEbYZNATYhsl7uxwn760pqVifkq2DSrZeYm4+lw9 jwWMtUoPzpg.CJYMoGl846nhiZrbbJ5b5twoLV6GRmkk/CfOxPXNzCtSoQA86HHq 7rRdhXSau/bY.EXc91tnhLjFzZxdBgrd+f4k=.-----END PRIVATE KEY-----. --estServerExampleBoundary.Content-Type: application/pkcs7-mime. .-----BEGIN PKCS7-----.MIIDPAYJKoZIhvcNAQcCoIIDLTCCAykCAQExADALB gkqhkiG9w0BBwGgggMPMIID.CzCCAfOgAwIBAgIBBTANBgkqhkiG9w0BAQUFADAX MRUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM2WhcNMTMwNzA 0MTgzOTM2WjAsMSowKAYDVQQD.EyFzZXJ2ZXJzaWRlIGtleSBnZW5lcmF0ZWQgcm VzcG9uc2UwggEiMA0GCSqGSIb3.DQEBAQUAA4IBDwAwggEKAoIBAQC0781l7tri0 yiiMb9ZZYch8zeizXrjMPF/Rxoz.2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+ DsSMtzxn4l+9tIsVDkAe4FyzN0hL.d/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImD V3blvaMUKDSJhVbQ+z/G1W1TRx3iW.i5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2Zlw Gcj4DxIgbx9vG0mftIIxM4TUX28KBb.aLgJbalsiuOx3C2bEyaSPerdzqgvXFHGG Ahg1FU8DQiQEkinn66GPMtm1SNgitxF.xWouFqpsax5MWn/i52TfEaF2PNThOuzK tilweJhkg0gMIQTXAgMBAAGjTTBLMAkG.A1UdEwQCMAAwHQYDVR0OBBYEFLylcQN 0D5xTfRdayv+0GDULR2+EMB8GA1UdIwQY.MBaAFIR/SsVuU7I5IC+5INpMScsubQ /zMA0GCSqGSIb3DQEBBQUAA4IBAQButIeM.DB9PkwlGGe7zqvUWVD8y99zowwV6A rAOXWX+JO0bihgMtZaUfvPCX/LhZVEKDAki.W5orjAEvIu10b6l38ZzX2oyJgkYy Mmbb14lzTsRyjiqFw9j1PXxwgZvhwcaCF4b7.eDUUBQIeZg3AnkQrEwnHR5oVIN5 8qo0P7PSKC3Vl3H6DlQh3y7w87nN12923/wk0.v/bS3lv7lDX3HdmbQD1r2KPtBs JGF4jMdstT7FTx32ZFKObycbK7WJ4LHytNJDci.4iXf+B0S3D6Zbf1cXj80/W+jC GvU0+4SV3cgEXFE5VQvXd8x40W4h0dTSkQCDPOS.nPj4Dl/PsLqX3lDboQAxAA== .-----END PKCS7-----.--estServerExampleBoundary--.This is the ep ilogue. It is also to be ignored.. In text format this is: HTTP/1.1 200 OK Status: 200 OK Content-Type: multipart/mixed ; boundary=estServerExampleBoundary Pritikin, et al. Expires January 11, 2013 [Page 44] Internet-Draft EST July 2012 This is the preamble. It is to be ignored, though it is a handy place for estServer to include an explanatory note including contact or support information. --estServerExampleBoundary Content-Type=application/pkcs8 -----BEGIN PRIVATE KEY----- MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC0781l7tri0yii Mb9ZZYch8zeizXrjMPF/Rxoz2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSM tzxn4l+9tIsVDkAe4FyzN0hLd/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blv aMUKDSJhVbQ+z/G1W1TRx3iWi5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4Dx Igbx9vG0mftIIxM4TUX28KBbaLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8 DQiQEkinn66GPMtm1SNgitxFxWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhk g0gMIQTXAgMBAAECggEANlrz8XNX/lxBELixK0H83o4aYKYqDKZfZkUN8hU33xpu Y/0scVbLbu46WzysoIfJFyUC+zFJnbMCCOPjGbI/4NWkEqc9TAlKz+wDo+hf5bf0 ypFrEmikHk8R3fkpnvKi69ldw0iYnqcFVhq7VtGrSmJcy6Hckwbk7EBoUZGL0wtp xlO6XlhksAvn8+75qoWzsNhi7S/L0IVCVLbUaV3hodTHlH5M4daFbqyRWD7UiPKt Q3hdw1rpyVZg8ZbBFp0Ej4f9GdRaq88SIKMKCDu3t9ibn/v1kEte+PxhuwyW+d0o hkKSEW0yLKCzQm5tujsPq0UVzPBkLJACUnFAi+a4AQKBgQDu6VLH2eYoTjPPTyAv vOJnNWP7oMzyJ4/eFqdE9m+2Ajm/0qaMY95ftZ+GpEKggvC6Z5DFevEmgH4Sg2+G gFd93diyRPScVbNE8SmpXxLPU2UoykVmICuQZzLDNE18B3buxAm2GJ219NEnZOec jPMOV/IcG1aLzTqQssL3zo/0gQKBgQDB4Olpg3EBggtJ/+dlkLHUw8c7Pe3UyLkS VxVsyQwioYt8xMeCWuPvPNFcOjcW53KN/YSpCVjpttKGsPtLibMlKYKgasEqgcvl Vb5OFtA/jNAP3mdAgCzBn6IF1NhVQe2dclo5puZ0gO38HDWq7EtqSi9Q0JSMg3YC QNcOORptVwKBgQCHrCafaYWDhA11/+g2U9x6Yd56ifF43rCbnV+2EQCVaqQi49xC w4AH+Bs0mdlgT5unL6MOEmgZxkRR/SP7TKzixHYHnpMOqLhaQV24Wk5TQHek92D7 wu8aXRB9vBj4g0CuDNO6/jWpm/KenXXN+Fka3ySVg4zdbVmBzJJdqYckgQKBgFXS zSBzGgwz1/F7AaDZK49m1wPnhyeBb0OqHwbX/LI71rZ1mWef+nSF9Juh/Y77B5/J UPdO9vgGgS00nRk0LIRP2s5OU5IQgQTVLvf8a1UmbVgI+KX511Yi5yMztEwRcjEX VM9ejXeXN0I57pvqG/xCOK3Kl2eYLh4TO9/E8WjjAoGAA1mqUV4Hnf4yvF1rydMp fpvoWekiiRE33iEbYZNATYhsl7uxwn760pqVifkq2DSrZeYm4+lw9jwWMtUoPzpg CJYMoGl846nhiZrbbJ5b5twoLV6GRmkk/CfOxPXNzCtSoQA86HHq7rRdhXSau/bY EXc91tnhLjFzZxdBgrd+f4k= -----END PRIVATE KEY----- --estServerExampleBoundary Content-Type: application/pkcs7-mime -----BEGIN PKCS7----- MIIDPAYJKoZIhvcNAQcCoIIDLTCCAykCAQExADALBgkqhkiG9w0BBwGgggMPMIID CzCCAfOgAwIBAgIBBTANBgkqhkiG9w0BAQUFADAXMRUwEwYDVQQDEwxlc3RFeGFt cGxlQ0EwHhcNMTIwNzA0MTgzOTM2WhcNMTMwNzA0MTgzOTM2WjAsMSowKAYDVQQD EyFzZXJ2ZXJzaWRlIGtleSBnZW5lcmF0ZWQgcmVzcG9uc2UwggEiMA0GCSqGSIb3 DQEBAQUAA4IBDwAwggEKAoIBAQC0781l7tri0yiiMb9ZZYch8zeizXrjMPF/Rxoz 2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSMtzxn4l+9tIsVDkAe4FyzN0hL d/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blvaMUKDSJhVbQ+z/G1W1TRx3iW i5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4DxIgbx9vG0mftIIxM4TUX28KBb aLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8DQiQEkinn66GPMtm1SNgitxF xWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhkg0gMIQTXAgMBAAGjTTBLMAkG Pritikin, et al. Expires January 11, 2013 [Page 45] Internet-Draft EST July 2012 A1UdEwQCMAAwHQYDVR0OBBYEFLylcQN0D5xTfRdayv+0GDULR2+EMB8GA1UdIwQY MBaAFIR/SsVuU7I5IC+5INpMScsubQ/zMA0GCSqGSIb3DQEBBQUAA4IBAQButIeM DB9PkwlGGe7zqvUWVD8y99zowwV6ArAOXWX+JO0bihgMtZaUfvPCX/LhZVEKDAki W5orjAEvIu10b6l38ZzX2oyJgkYyMmbb14lzTsRyjiqFw9j1PXxwgZvhwcaCF4b7 eDUUBQIeZg3AnkQrEwnHR5oVIN58qo0P7PSKC3Vl3H6DlQh3y7w87nN12923/wk0 v/bS3lv7lDX3HdmbQD1r2KPtBsJGF4jMdstT7FTx32ZFKObycbK7WJ4LHytNJDci 4iXf+B0S3D6Zbf1cXj80/W+jCGvU0+4SV3cgEXFE5VQvXd8x40W4h0dTSkQCDPOS nPj4Dl/PsLqX3lDboQAxAA== -----END PKCS7----- --estServerExampleBoundary-- This is the epilogue. It is also to be ignored. Authors' Addresses Max Pritikin (editor) Cisco Systems, Inc. 510 McCarthy Drive Milpitas, CA 95035 USA Email: pritikin@cisco.com Peter E. Yee (editor) AKAYLA, Inc. 7150 Moorland Drive Clarksville, MD 21029 USA Email: peter@akayla.com Dan Harkins (editor) Aruba Networks 1322 Crossman Avenue Sunnyvale, CA 94089-1113 USA Email: dharkins@arubanetworks.com Pritikin, et al. Expires January 11, 2013 [Page 46]