< draft-ietf-tls-oob-pubkey-07.txt   draft-ietf-tls-oob-pubkey-08.txt >
TLS P. Wouters, Ed. TLS P. Wouters, Ed.
Internet-Draft Red Hat Internet-Draft Red Hat
Intended status: Standards Track H. Tschofenig, Ed. Intended status: Standards Track H. Tschofenig, Ed.
Expires: August 19, 2013 Nokia Siemens Networks Expires: January 17, 2014 Nokia Siemens Networks
J. Gilmore J. Gilmore
S. Weiler S. Weiler
SPARTA, Inc. SPARTA, Inc.
T. Kivinen T. Kivinen
AuthenTec AuthenTec
February 15, 2013 July 16, 2013
Out-of-Band Public Key Validation for Transport Layer Security (TLS) Out-of-Band Public Key Validation for Transport Layer Security (TLS)
draft-ietf-tls-oob-pubkey-07.txt draft-ietf-tls-oob-pubkey-08.txt
Abstract Abstract
This document specifies a new certificate type for exchanging raw This document specifies a new certificate type and two TLS
public keys in Transport Layer Security (TLS) and Datagram Transport extensions, one for the client and one for the server, for exchanging
Layer Security (DTLS) for use with out-of-band public key validation. raw public keys in Transport Layer Security (TLS) and Datagram
Currently, TLS authentication can only occur via X.509-based Public Transport Layer Security (DTLS) for use with out-of-band public key
Key Infrastructure (PKI) or OpenPGP certificates. By specifying a validation.
minimum resource for raw public key exchange, implementations can use
alternative public key validation methods.
One such alternative public key valiation method is offered by the
DNS-Based Authentication of Named Entities (DANE) together with DNS
Security. Another alternative is to utilize pre-configured keys, as
is the case with sensors and other embedded devices. The usage of
raw public keys, instead of X.509-based certificates, leads to a
smaller code footprint.
This document introduces the support for raw public keys in TLS.
Status of this Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 19, 2013. This Internet-Draft will expire on January 17, 2014.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. New TLS Extension . . . . . . . . . . . . . . . . . . . . . . 5 3. New TLS Extension . . . . . . . . . . . . . . . . . . . . . . 3
4. TLS Handshake Extension . . . . . . . . . . . . . . . . . . . 8 4. TLS Handshake Extension . . . . . . . . . . . . . . . . . . . 7
4.1. Client Hello . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. Client Hello . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Server Hello . . . . . . . . . . . . . . . . . . . . . . . 9 4.2. Server Hello . . . . . . . . . . . . . . . . . . . . . . 7
4.3. Certificate Request . . . . . . . . . . . . . . . . . . . 9 4.3. Certificate Request . . . . . . . . . . . . . . . . . . . 7
4.4. Other Handshake Messages . . . . . . . . . . . . . . . . . 9 4.4. Other Handshake Messages . . . . . . . . . . . . . . . . 7
4.5. Client authentication . . . . . . . . . . . . . . . . . . 9 4.5. Client authentication . . . . . . . . . . . . . . . . . . 8
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Example Encoding . . . . . . . . . . . . . . . . . . 15 Appendix A. Example Encoding . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
Traditionally, TLS server public keys are obtained in PKIX containers Traditionally, TLS client and server public keys are obtained in PKIX
in-band using the TLS handshake and validated using trust anchors containers in-band using the TLS handshake and validated using trust
based on a [PKIX] certification authority (CA). This method can add anchors based on a [PKIX] certification authority (CA). This method
a complicated trust relationship that is difficult to validate. can add a complicated trust relationship that is difficult to
Examples of such complexity can be seen in [Defeating-SSL]. validate. Examples of such complexity can be seen in
[Defeating-SSL].
Alternative methods are available that allow a TLS client to obtain Alternative methods are available that allow a TLS clients/servers to
the TLS server public key: obtain the TLS servers/client public key:
o The TLS server public key is obtained from a DNSSEC secured o TLS clients can obtain the TLS server public key from a DNSSEC
resource records using DANE [RFC6698]. secured resource records using DANE [RFC6698].
o The TLS server public key is obtained from a [PKIX] certificate o The TLS client or server public key is obtained from a [PKIX]
chain from an Lightweight Directory Access Protocol (LDAP) [LDAP] certificate chain from an Lightweight Directory Access Protocol
server. (LDAP) [LDAP] server or web page.
o The TLS client and server public key is provisioned into the o The TLS client and server public key is provisioned into the
operating system firmware image, and updated via software updates. operating system firmware image, and updated via software updates.
For example:
Some smart objects use the UDP-based Constrained Application Protocol Some smart objects use the UDP-based Constrained Application
(CoAP) [I-D.ietf-core-coap] to interact with a Web server to upload Protocol (CoAP) [I-D.ietf-core-coap] to interact with a Web server
sensor data at a regular intervals, such as temperature readings. to upload sensor data at a regular intervals, such as temperature
CoAP [I-D.ietf-core-coap] can utilize DTLS for securing the client- readings. CoAP [I-D.ietf-core-coap] can utilize DTLS for securing
to-server communication. As part of the manufacturing process, the the client-to-server communication. As part of the manufacturing
embeded device may be configured with the address and the public key process, the embedded device may be configured with the address
of a dedicated CoAP server, as well as a public key for the client and the public key of a dedicated CoAP server, as well as a public
itself. The usage of X.509-based PKIX certificates [PKIX] may not key for the client itself.
suit all smart object deployments and would therefore be an
unneccesarry burden.
The Transport Layer Security (TLS) Protocol Version 1.2 [RFC5246] The mechanism defined herein only provides authentication when an
provides a framework for extensions to TLS as well as guidelines for out-of-band mechanism is also used to bind the public key to the
designing such extensions. This document registers a new value to entity presenting the key.
the IANA certificate types registry for the support of raw public
keys. This document registers a new value to the IANA certificate types
registry for the support of raw public keys. It also defines two new
TLS extensions, "client_certificate_type" and
"server_certificate_type".
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. New TLS Extension 3. New TLS Extension
This section describes the changes to the TLS handshake message This section describes the changes to the TLS handshake message
contents when raw public key certificates are to be used. Figure 4 contents when raw public keys are to be used. Figure 4 illustrates
illustrates the exchange of messages as described in the sub-sections the exchange of messages as described in the sub-sections below. The
below. The client and the server exchange make use of two new TLS client and the server exchange make use of two new TLS extensions,
extensions, namely 'client_certificate_type' and namely 'client_certificate_type' and 'server_certificate_type', and
'server_certificate_type', and an already available IANA TLS an already available IANA TLS Certificate Type registry
Certificate Type registry [TLS-Certificate-Types-Registry] to [TLS-Certificate-Types-Registry] to indicate their ability and desire
indicate their ability and desire to exchange raw public keys. These to exchange raw public keys. These raw public keys, in the form of a
raw public keys, in the form of a SubjectPublicKeyInfo structure, are SubjectPublicKeyInfo structure, are then carried inside the
then carried inside the Certificate payload. The Certificate and the Certificate payload. The Certificate and the SubjectPublicKeyInfo
SubjectPublicKeyInfo structure is shown in Figure 1. structure is shown in Figure 1.
opaque ASN.1Cert<1..2^24-1>; opaque ASN.1Cert<1..2^24-1>;
struct { struct {
select(certificate_type){ select(certificate_type){
// certificate type defined in this document.
// certificate type defined in this document.
case RawPublicKey: case RawPublicKey:
opaque ASN.1_subjectPublicKeyInfo<1..2^24-1>; opaque ASN.1_subjectPublicKeyInfo<1..2^24-1>;
// X.509 certificate defined in RFC 5246 // X.509 certificate defined in RFC 5246
case X.509: case X.509:
ASN.1Cert certificate_list<0..2^24-1>; ASN.1Cert certificate_list<0..2^24-1>;
// Additional certificate type based on TLS // Additional certificate type based on TLS
// Certificate Type Registry // Certificate Type Registry
}; };
} Certificate; } Certificate;
Figure 1: TLS Certificate Structure. Figure 1: TLS Certificate Structure.
The SubjectPublicKeyInfo structure is defined in Section 4.1 of RFC The SubjectPublicKeyInfo structure is defined in Section 4.1 of RFC
5280 [PKIX] and does not only contain the raw keys, such as the 5280 [PKIX] and does not only contain the raw keys, such as the
public exponent and the modulus of an RSA public key, but also an public exponent and the modulus of an RSA public key, but also an
algorithm identifier. The structure, as shown in Figure 2, is algorithm identifier. The algorithm identifier can also include
encoded in an ASN.1 format and therefore contains length information parameters. The structure, as shown in Figure 2, is encoded in an
as well. An example is provided in Appendix A. DER encoded ASN.1 format [X.690] and therefore contains length
information as well. An example is provided in Appendix A.
SubjectPublicKeyInfo ::= SEQUENCE { SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier, algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING } subjectPublicKey BIT STRING }
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL }
Figure 2: SubjectPublicKeyInfo ASN.1 Structure. Figure 2: SubjectPublicKeyInfo ASN.1 Structure.
The algorithm identifiers are Object Identifiers (OIDs). RFC 3279 The algorithm identifiers are Object Identifiers (OIDs). RFC 3279
[RFC3279], for example, defines the following OIDs shown in Figure 3. [RFC3279] and [RFC5480] define the following OIDs shown in Figure 3.
Key Type | Document | OID Key Type | Document | OID
RSA | Section 2.3.1 of RFC 3279 | 1.2.840.113549.1.1 -----------------------+----------------------------+-------------------
.......................|............................|................... RSA | Section 2.3.1 of RFC 3279 | 1.2.840.113549.1.1
Digital Signature | | .......................|............................|...................
Algorithm (DSS) | Section 2.3.2 of RFC 3279 | 1.2.840.10040.4.1 Digital Signature | |
.......................|............................|................... Algorithm (DSS) | Section 2.3.2 of RFC 3279 | 1.2.840.10040.4.1
Elliptic Curve | | .......................|............................|...................
Digital Signature | | Elliptic Curve | |
Algorithm (ECDSA) | Section 2.3.5 of RFC 3279 | 1.2.840.10045.2.1 Digital Signature | |
Algorithm (ECDSA) | Section 2.3.5 of RFC 5480 | 1.2.840.10045.2.1
-----------------------+----------------------------+-------------------
Figure 3: Example Algorithm Identifiers. Figure 3: Example Algorithm Object Identifiers.
The message exchange in Figure 4 shows the 'client_certificate_type' The message exchange in Figure 4 shows the 'client_certificate_type'
and 'server_certificate_type' extensions added to the client and and 'server_certificate_type' extensions added to the client and
server hello messages. server hello messages.
client_hello, client_hello,
client_certificate_type client_certificate_type
server_certificate_type -> server_certificate_type ->
<- server_hello, <- server_hello,
skipping to change at page 8, line 44 skipping to change at page 7, line 11
No new cipher suites are required to use raw public keys. All No new cipher suites are required to use raw public keys. All
existing cipher suites that support a key exchange method compatible existing cipher suites that support a key exchange method compatible
with the defined extension can be used. with the defined extension can be used.
4. TLS Handshake Extension 4. TLS Handshake Extension
4.1. Client Hello 4.1. Client Hello
In order to indicate the support of out-of-band raw public keys, In order to indicate the support of out-of-band raw public keys,
clients MUST include the 'client_certificate_type' and clients MUST include the 'client_certificate_type' and
'server_certificate_type' extensions extended client hello message. 'server_certificate_type' extensions in an extended client hello
The hello extension mechanism is described in TLS 1.2 [RFC5246]. message. The hello extension mechanism is described in TLS 1.2
[RFC5246].
4.2. Server Hello 4.2. Server Hello
If the server receives a client hello that contains the If the server receives a client hello that contains the
'client_certificate_type' and 'server_certificate_type' extensions 'client_certificate_type' and 'server_certificate_type' extensions
and chooses a cipher suite then three outcomes are possible: and chooses a cipher suite then three outcomes are possible:
1. The server does not support the extension defined in this 1. The server does not support the extension defined in this
document. In this case the server returns the server hello document. In this case the server returns the server hello
without the extensions defined in this document. without the extensions defined in this document.
skipping to change at page 9, line 31 skipping to change at page 7, line 41
does not have a certificate type in common with the client. In does not have a certificate type in common with the client. In
this case the server terminate the session with a fatal alert of this case the server terminate the session with a fatal alert of
type "unsupported_certificate". type "unsupported_certificate".
If the TLS server also requests a certificate from the client (via If the TLS server also requests a certificate from the client (via
the certificate_request) it MUST include the the certificate_request) it MUST include the
'client_certificate_type' extension with a value chosen from the list 'client_certificate_type' extension with a value chosen from the list
of client-supported certificates types (as provided in the of client-supported certificates types (as provided in the
'client_certificate_type' of the client hello). 'client_certificate_type' of the client hello).
If the client indicated the support of raw public keys in the If the client hello indicates support of raw public keys in the
'client_certificate_type' extension in the client hello and the 'client_certificate_type' extension and the server chooses to use raw
server is able to provide such raw public key then the TLS server public keys then the TLS server MUST place the SubjectPublicKeyInfo
MUST place the SubjectPublicKeyInfo structure into the Certificate structure into the Certificate payload.
payload. The public key algorithm MUST match the selected key
exchange algorithm.
4.3. Certificate Request 4.3. Certificate Request
The semantics of this message remain the same as in the TLS The semantics of this message remain the same as in the TLS
specification. specification.
4.4. Other Handshake Messages 4.4. Other Handshake Messages
All the other handshake messages are identical to the TLS All the other handshake messages are identical to the TLS
specification. specification.
4.5. Client authentication 4.5. Client authentication
Client authentication by the TLS server is supported only through Client authentication by the TLS server is supported only through
authentication of the received client SubjectPublicKeyInfo via an authentication of the received client SubjectPublicKeyInfo via an
out-of-band method. out-of-band method.
5. Examples 5. Examples
skipping to change at page 10, line 17 skipping to change at page 8, line 25
Figure 6, Figure 7, and Figure 8 illustrate example exchanges. Figure 6, Figure 7, and Figure 8 illustrate example exchanges.
The first example shows an exchange where the TLS client indicates The first example shows an exchange where the TLS client indicates
its ability to receive and validate raw public keys from the server. its ability to receive and validate raw public keys from the server.
In our example the client is quite restricted since it is unable to In our example the client is quite restricted since it is unable to
process other certificate types sent by the server. It also does not process other certificate types sent by the server. It also does not
have credentials (at the TLS layer) it could send. The have credentials (at the TLS layer) it could send. The
'client_certificate_type' extension indicates this in [1]. When the 'client_certificate_type' extension indicates this in [1]. When the
TLS server receives the client hello it processes the TLS server receives the client hello it processes the
'client_certificate_type' extension. Since it also has a raw public 'client_certificate_type' extension. Since it also has a raw public
key it indicates in [2] that it had choosen to place the key it indicates in [2] that it had chosen to place the
SubjectPublicKeyInfo structure into the Certificate payload [3]. The SubjectPublicKeyInfo structure into the Certificate payload [3]. The
client uses this raw public key in the TLS handshake and an out-of- client uses this raw public key in the TLS handshake and an out-of-
band technique, such as DANE, to verify its validity. band technique, such as DANE, to verify its validity.
client_hello, client_hello,
server_certificate_type=(RawPublicKey) -> // [1] server_certificate_type=(RawPublicKey) -> // [1]
<- server_hello, <- server_hello,
server_certificate_type=(RawPublicKey), // [2] server_certificate_type=(RawPublicKey), // [2]
certificate, // [3] certificate, // [3]
server_key_exchange, server_key_exchange,
server_hello_done server_hello_done
client_key_exchange, client_key_exchange,
change_cipher_spec, change_cipher_spec,
finished -> finished ->
<- change_cipher_spec, <- change_cipher_spec,
finished finished
Application Data <-------> Application Data Application Data <-------> Application Data
Figure 6: Example with Raw Public Key provided by the TLS Server Figure 6: Example with Raw Public Key provided by the TLS Server
In our second example the TLS client as well as the TLS server use In our second example the TLS client as well as the TLS server use
raw public keys. This is a use case envisioned for smart object raw public keys. This is a use case envisioned for smart object
networking. The TLS client in this case is an embedded device that networking. The TLS client in this case is an embedded device that
is configured with a raw public key for use with TLS and is also able is configured with a raw public key for use with TLS and is also able
to process raw public keys sent by the server. Therefore, it to process raw public keys sent by the server. Therefore, it
indicates these capabilities in [1]. As in the previously shown indicates these capabilities in [1]. As in the previously shown
example the server fulfills the client's request, indicates this via example the server fulfills the client's request, indicates this via
the "RawPublicKey" value in the server_certificate_type payload, and the "RawPublicKey" value in the server_certificate_type payload, and
provides a raw public key into the Certificate payload back to the provides a raw public key into the Certificate payload back to the
client (see [3]). The TLS server, however, demands client client (see [3]). The TLS server, however, demands client
authentication and therefore a certificate_request is added [4]. The authentication and therefore a certificate_request is added [4]. The
certificate_type payload in [2] indicates that the TLS server accepts certificate_type payload in [2] indicates that the TLS server accepts
raw public keys. The TLS client, who has a raw public key pre- raw public keys. The TLS client, who has a raw public key pre-
provisioned, returns it in the Certificate payload [5] to the server. provisioned, returns it in the Certificate payload [5] to the server.
client_hello, client_hello,
client_certificate_type=(RawPublicKey) // [1] client_certificate_type=(RawPublicKey) // [1]
server_certificate_type=(RawPublicKey) // [1] server_certificate_type=(RawPublicKey) // [1]
-> ->
<- server_hello, <- server_hello,
server_certificate_type=(RawPublicKey)//[2] server_certificate_type=(RawPublicKey)//[2]
certificate, // [3] certificate, // [3]
client_certificate_type=(RawPublicKey)//[4] client_certificate_type=(RawPublicKey)//[4]
certificate_request, // [4] certificate_request, // [4]
server_key_exchange, server_key_exchange,
server_hello_done server_hello_done
certificate, // [5] certificate, // [5]
client_key_exchange, client_key_exchange,
change_cipher_spec, change_cipher_spec,
finished -> finished ->
<- change_cipher_spec, <- change_cipher_spec,
finished finished
Application Data <-------> Application Data Application Data <-------> Application Data
Figure 7: Example with Raw Public Key provided by the TLS Server and Figure 7: Example with Raw Public Key provided by the TLS Server and
the Client the Client
In our last example we illustrate a combination of raw public key and In our last example we illustrate a combination of raw public key and
X.509 usage. The client uses a raw public key for client X.509 usage. The client uses a raw public key for client
authentication but the server provides an X.509 certificate. This authentication but the server provides an X.509 certificate. This
exchange starts with the client indicating its ability to process exchange starts with the client indicating its ability to process
X.509 certificates provided by the server, and the ability to send X.509 certificates provided by the server, and the ability to send
raw public keys (see [1]). The server provides the X.509 certificate raw public keys (see [1]). The server provides the X.509 certificate
in [3] with the indication present in [2]. For client authentication in [3] with the indication present in [2]. For client authentication
the server indicates in [4] that it selected the raw public key the server indicates in [4] that it selected the raw public key
format and requests a certificate from the client in [5]. The TLS format and requests a certificate from the client in [5]. The TLS
client provides a raw public key in [6] after receiving and client provides a raw public key in [6] after receiving and
processing the TLS server hello message. processing the TLS server hello message.
client_hello, client_hello,
server_certificate_type=(X.509) server_certificate_type=(X.509)
client_certificate_type=(RawPublicKey) // [1] client_certificate_type=(RawPublicKey) // [1]
-> ->
<- server_hello, <- server_hello,
server_certificate_type=(X.509)//[2] server_certificate_type=(X.509)//[2]
certificate, // [3] certificate, // [3]
client_certificate_type=(RawPublicKey)//[4] client_certificate_type=(RawPublicKey)//[4]
certificate_request, // [5] certificate_request, // [5]
server_key_exchange, server_key_exchange,
server_hello_done server_hello_done
certificate, // [6] certificate, // [6]
client_key_exchange, client_key_exchange,
change_cipher_spec, change_cipher_spec,
finished -> finished ->
<- change_cipher_spec, <- change_cipher_spec,
finished finished
Application Data <-------> Application Data Application Data <-------> Application Data
Figure 8: Hybrid Certificate Example Figure 8: Hybrid Certificate Example
6. Security Considerations 6. Security Considerations
The transmission of raw public keys, as described in this document, The transmission of raw public keys, as described in this document,
provides benefits by lowering the over-the-air transmission overhead provides benefits by lowering the over-the-air transmission overhead
since raw public keys are quite naturally smaller than an entire since raw public keys are quite naturally smaller than an entire
certificate. There are also advantages from a codesize point of view certificate. There are also advantages from a code size point of
for parsing and processing these keys. The crytographic procedures view for parsing and processing these keys. The cryptographic
for assocating the public key with the possession of a private key procedures for associating the public key with the possession of a
also follows standard procedures. private key also follows standard procedures.
The main security challenge is, however, how to associate the public The main security challenge is, however, how to associate the public
key with a specific entity. This information will be needed to make key with a specific entity. Without a secure binding between
authorization decisions. Without a secure binding, man-in-the-middle identity and key the protocol will be vulnerable to masquerade and
attacks may be the consequence. This document assumes that such man-in-the-middle attacks. This document assumes that such binding
binding can be made out-of-band and we list a few examples in can be made out-of-band and we list a few examples in Section 1.
Section 1. DANE [RFC6698] offers one such approach. If public keys DANE [RFC6698] offers one such approach. In order to address these
vulnerabilities, specifications that make use of the extension MUST
specify how the identity and public key are bound. If public keys
are obtained using DANE, these public keys are authenticated via are obtained using DANE, these public keys are authenticated via
DNSSEC. Pre-configured keys is another out of band method for DNSSEC. Pre-configured keys is another out of band method for
authenticating raw public keys. While pre-configured keys are not authenticating raw public keys. While pre-configured keys are not
suitable for a generic Web-based e-commerce environment such keys are suitable for a generic Web-based e-commerce environment such keys are
a reasonable approach for many smart object deployments where there a reasonable approach for many smart object deployments where there
is a close relationship between the software running on the device is a close relationship between the software running on the device
and the server-side communication endpoint. Regardless of the chosen and the server-side communication endpoint. Regardless of the chosen
mechanism for out-of-band public key validation an assessment of the mechanism for out-of-band public key validation an assessment of the
most suitable approach has to be made prior to the start of a most suitable approach has to be made prior to the start of a
deployment to ensure the security of the system. deployment to ensure the security of the system.
skipping to change at page 13, line 39 skipping to change at page 11, line 47
substantially shaped the document and we would like to thank the substantially shaped the document and we would like to thank the
meeting participants for their input. The support for hashes of meeting participants for their input. The support for hashes of
public keys has been moved to [I-D.ietf-tls-cached-info] after the public keys has been moved to [I-D.ietf-tls-cached-info] after the
discussions at the IETF#82 meeting. discussions at the IETF#82 meeting.
We would like to thank the following persons for their review We would like to thank the following persons for their review
comments: Martin Rex, Bill Frantz, Zach Shelby, Carsten Bormann, comments: Martin Rex, Bill Frantz, Zach Shelby, Carsten Bormann,
Cullen Jennings, Rene Struik, Alper Yegin, Jim Schaad, Barry Leiba, Cullen Jennings, Rene Struik, Alper Yegin, Jim Schaad, Barry Leiba,
Paul Hoffman, Robert Cragie, Nikos Mavrogiannopoulos, Phil Hunt, John Paul Hoffman, Robert Cragie, Nikos Mavrogiannopoulos, Phil Hunt, John
Bradley, Klaus Hartke, Stefan Jucker, Kovatsch Matthias, Daniel Kahn Bradley, Klaus Hartke, Stefan Jucker, Kovatsch Matthias, Daniel Kahn
Gillmor, and James Manger. Nikos Mavrogiannopoulos contributed the Gillmor, Peter Sylvester, and James Manger. Nikos Mavrogiannopoulos
design for re-using the certificate type registry. Barry Leiba contributed the design for re-using the certificate type registry.
contributed guidance for the IANA consideration text. Stefan Jucker,
Kovatsch Matthias, and Klaus Hartke provided implementation feedback
regarding the SubjectPublicKeyInfo structure.
Finally, we would like to thank our TLS working group chairs, Eric Barry Leiba contributed guidance for the IANA consideration text.
Rescorla and Joe Salowey, for their guidance and support. Stefan Jucker, Kovatsch Matthias, and Klaus Hartke provided
implementation feedback regarding the SubjectPublicKeyInfo structure.
We would like to thank our TLS working group chairs, Eric Rescorla
and Joe Salowey, for their guidance and support. Finally, we would
like to thank Sean Turner, who is the responsible security area
director for this work for his review comments and suggestions.
9. References 9. References
9.1. Normative References 9.1. Normative References
[PKIX] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [PKIX] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008. (CRL) Profile", RFC 5280, May 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, April 2002.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, March 2009.
[TLS-Certificate-Types-Registry] [TLS-Certificate-Types-Registry]
"TLS Certificate Types Registry", February 2013, <http:// , "TLS Certificate Types Registry", February 2013, <http:/
www.iana.org/assignments/ /www.iana.org/assignments/tls-extensiontype-values#tls-
tls-extensiontype-values#tls-extensiontype-values-2>. extensiontype-values-2>.
[X.690] , "Information technology - ASN.1 encoding rules: >
Specification of Basic Encoding Rules (BER), Canonical >
Encoding Rules (CER) and Distinguished Encoding Rules >
(DER).", RFC 5280, 2002.
9.2. Informative References 9.2. Informative References
[ASN.1-Dump] [ASN.1-Dump]
Gutmann, P., "ASN.1 Object Dump Program", February 2013, Gutmann, P., "ASN.1 Object Dump Program", February 2013,
<http://www.cs.auckland.ac.nz/~pgut001/>. <http://www.cs.auckland.ac.nz/~pgut001/>.
[Defeating-SSL] [Defeating-SSL]
Marlinspike, M., "New Tricks for Defeating SSL in Marlinspike, M., "New Tricks for Defeating SSL in
Practice", February 2009, <http://www.blackhat.com/ Practice", February 2009, <http://www.blackhat.com/
presentations/bh-dc-09/Marlinspike/ presentations/bh-dc-09/Marlinspike/BlackHat-DC-09
BlackHat-DC-09-Marlinspike-Defeating-SSL.pdf>. -Marlinspike-Defeating-SSL.pdf>.
[I-D.ietf-core-coap] [I-D.ietf-core-coap]
Shelby, Z., Hartke, K., Bormann, C., and B. Frank, Shelby, Z., Hartke, K., and C. Bormann, "Constrained
"Constrained Application Protocol (CoAP)", Application Protocol (CoAP)", draft-ietf-core-coap-18
draft-ietf-core-coap-13 (work in progress), December 2012. (work in progress), June 2013.
[I-D.ietf-tls-cached-info] [I-D.ietf-tls-cached-info]
Santesson, S. and H. Tschofenig, "Transport Layer Security Santesson, S. and H. Tschofenig, "Transport Layer Security
(TLS) Cached Information Extension", (TLS) Cached Information Extension", draft-ietf-tls-
draft-ietf-tls-cached-info-13 (work in progress), cached-info-14 (work in progress), March 2013.
September 2012.
[LDAP] Sermersheim, J., "Lightweight Directory Access Protocol [LDAP] Sermersheim, J., "Lightweight Directory Access Protocol
(LDAP): The Protocol", RFC 4511, June 2006. (LDAP): The Protocol", RFC 4511, June 2006.
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, April 2002.
[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication [RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS) of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, August 2012. Protocol: TLSA", RFC 6698, August 2012.
Appendix A. Example Encoding Appendix A. Example Encoding
For example, the following hex sequence describes a For example, the following hex sequence describes a
SubjectPublicKeyInfo structure inside the certificate payload: SubjectPublicKeyInfo structure inside the certificate payload:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
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