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Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Obsolete informational reference (is this intentional?): RFC 4395 (Obsoleted by RFC 7595) Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Pechanec 3 Internet-Draft D. Moffat 4 Intended status: Standards Track Oracle Corporation 5 Expires: March 29, 2015 September 25, 2014 7 The PKCS#11 URI Scheme 8 draft-pechanec-pkcs11uri-15 10 Abstract 12 This memo specifies a PKCS#11 Uniform Resource Identifier (URI) 13 Scheme for identifying PKCS#11 objects stored in PKCS#11 tokens, for 14 identifying PKCS#11 tokens themselves, or for identifying PKCS#11 15 libraries. The URI is based on how PKCS#11 objects, tokens, and 16 libraries are identified in the PKCS#11 Cryptographic Token Interface 17 Standard. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on March 29, 2015. 36 Copyright Notice 38 Copyright (c) 2014 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 2. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 3 55 3. PKCS#11 URI Scheme Definition . . . . . . . . . . . . . . . . 3 56 3.1. PKCS#11 URI Scheme Name . . . . . . . . . . . . . . . . . 4 57 3.2. PKCS#11 URI Scheme Status . . . . . . . . . . . . . . . . 4 58 3.3. PKCS#11 URI Scheme Syntax . . . . . . . . . . . . . . . . 4 59 3.4. PKCS#11 URI Scheme Query Attribute Semantics . . . . . . 8 60 3.5. PKCS#11 URI Matching Guidelines . . . . . . . . . . . . . 10 61 3.6. PKCS#11 URI Comparison . . . . . . . . . . . . . . . . . 11 62 4. Examples of PKCS#11 URIs . . . . . . . . . . . . . . . . . . 12 63 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 64 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15 65 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 66 7.1. Normative References . . . . . . . . . . . . . . . . . . 15 67 7.2. Informative References . . . . . . . . . . . . . . . . . 16 68 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 70 1. Introduction 72 The PKCS #11: Cryptographic Token Interface Standard [pkcs11_spec] 73 specifies an API, called Cryptoki, for devices which hold 74 cryptographic information and perform cryptographic functions. 75 Cryptoki, pronounced crypto-key and short for cryptographic token 76 interface, follows a simple object-based approach, addressing the 77 goals of technology independence (any kind of device may be used) and 78 resource sharing (multiple applications may access multiple devices), 79 presenting applications with a common, logical view of the device - a 80 cryptographic token. 82 It is desirable for applications or libraries that work with PKCS#11 83 tokens to accept a common identifier that consumers could use to 84 identify an existing PKCS#11 storage object in a PKCS#11 token, an 85 existing token itself, or an existing Cryptoki library (also called a 86 producer, module, or provider). The set of storage object types that 87 can be stored in a PKCS#11 token includes a certificate, a public, 88 private or secret key, and a data object. These objects can be 89 uniquely identifiable via the PKCS#11 URI scheme defined in this 90 document. The set of attributes describing a storage object can 91 contain an object label, its type, and its ID. The set of attributes 92 that identifies a PKCS#11 token can contain a token label, a 93 manufacturer name, a serial number, and a token model. Attributes 94 that can identify a Cryptoki library are a library manufacturer, a 95 library description, and a library version. Library attributes may 96 be necessary to use if more than one Cryptoki library provides a 97 token and/or PKCS#11 objects of the same name. A set of query 98 attributes is provided as well. 100 The PKCS#11 URI cannot identify other objects defined in the 101 specification [pkcs11_spec] aside from storage objects. For example, 102 objects not identifiable by a PKCS#11 URI include a hardware feature 103 and mechanism. Note that a Cryptoki library does not have to provide 104 for storage objects at all. The URI can still be used to identify a 105 specific PKCS#11 token or an API producer in such a case. 107 A subset of existing PKCS#11 structure members and object attributes 108 was chosen believed to be sufficient in uniquely identifying a 109 PKCS#11 token, storage object, or library in a configuration file, on 110 a command line, or in a configuration property of something else. 111 Should there be a need for a more complex information exchange on 112 PKCS#11 entities a different means of data marshalling should be 113 chosen accordingly. 115 A PKCS#11 URI is not intended to be used to create new PKCS#11 116 objects in tokens, or to create PKCS#11 tokens. It is solely to be 117 used to identify and work with existing storage objects and tokens 118 through the PKCS#11 API, or identify Cryptoki libraries themselves. 120 The URI scheme defined in this document is designed specifically with 121 a mapping to the PKCS#11 API in mind. The URI uses the scheme, path 122 and query components defined in the Uniform Resource Identifier 123 (URI): Generic Syntax [RFC3986] document. The URI does not use the 124 hierarchical element for a naming authority in the path since the 125 authority part could not be mapped to PKCS#11 API elements. The URI 126 does not use the fragment component. 128 If an application has no access to a producer or producers of the 129 PKCS#11 API the query component module attributes can be used. 130 However, the PKCS#11 URI consumer can always decide to provide its 131 own adequate user interface to locate and load PKCS#11 API producers. 133 2. Contributors 135 Stef Walter, Nikos Mavrogiannopoulos, Nico Williams, Dan Winship, and 136 Jaroslav Imrich contributed to the development of this document. 138 3. PKCS#11 URI Scheme Definition 140 In accordance with [RFC4395], this section provides the information 141 required to register the PKCS#11 URI scheme. 143 3.1. PKCS#11 URI Scheme Name 145 pkcs11 147 3.2. PKCS#11 URI Scheme Status 149 Permanent. 151 3.3. PKCS#11 URI Scheme Syntax 153 The PKCS#11 URI is a sequence of attribute value pairs separated by a 154 semicolon that form a one level path component, optionally followed 155 by a query. In accordance with Section 2.5 of [RFC3986], the data 156 should first be encoded as octets according to the UTF-8 character 157 encoding [RFC3629]; then only those octets that do not correspond to 158 characters in the unreserved set or to permitted characters from the 159 reserved set should be percent-encoded. This specification suggests 160 one allowable exception to that rule for the "id" attribute, as 161 stated later in this section. Grammar rules "unreserved" and "pct- 162 encoded" in the PKCS#11 URI specification below are imported from 163 [RFC3986]. As a special case, note that according to Appendix A of 164 [RFC3986], a space must be percent-encoded. 166 PKCS#11 specification imposes various limitations on the value of 167 attributes, be it a more restrictive character set for the "serial" 168 attribute or fixed sized buffers for almost all the others, including 169 "token", "manufacturer", and "model" attributes. However, the 170 PKCS#11 URI notation does not impose such limitations aside from 171 removing generic and PKCS#11 URI delimiters from a permitted 172 character set. We believe that being too restrictive on the 173 attribute values could limit the PKCS#11 URI usefulness. What is 174 more, possible future changes to the PKCS#11 specification should not 175 affect existing attributes. 177 A PKCS#11 URI takes the form (for explanation of Augmented BNF, see 178 [RFC5234]): 180 pk11-URI = "pkcs11" ":" pk11-path *1("?" pk11-query) 181 ; Path component and its attributes. Path may be empty. 182 pk11-path = *1(pk11-pattr *(";" pk11-pattr)) 183 pk11-pattr = pk11-token / pk11-manuf / pk11-serial / 184 pk11-model / pk11-lib-manuf / 185 pk11-lib-ver / pk11-lib-desc / 186 pk11-object / pk11-type / pk11-id / 187 pk11-x-pattr 188 ; Query component and its attributes. Query may be empty. 189 pk11-qattr = pk11-pin-source / pk11-pin-value / 190 pk11-module-name / pk11-module-path / 191 pk11-x-qattr 192 pk11-query = *1(pk11-qattr *("&" pk11-qattr)) 193 ; RFC 3986 section 2.2 mandates all potentially reserved characters 194 ; that do not conflict with actual delimiters of the URI do not have 195 ; to be percent-encoded. 196 pk11-res-avail = ":" / "[" / "]" / "@" / "!" / "$" / 197 "'" / "(" / ")" / "*" / "+" / "," / "=" 198 pk11-path-res-avail = pk11-res-avail / "&" 199 ; We allow "/" and "?" in the query to be unencoded but "&" must 200 ; be encoded since it may be used as a delimiter in the component. 201 pk11-query-res-avail = pk11-res-avail / "/" / "?" / "|" 202 pk11-pchar = unreserved / pk11-path-res-avail / pct-encoded 203 pk11-qchar = unreserved / pk11-query-res-avail / pct-encoded 204 pk11-token = "token" "=" *pk11-pchar 205 pk11-manuf = "manufacturer" "=" *pk11-pchar 206 pk11-serial = "serial" "=" *pk11-pchar 207 pk11-model = "model" "=" *pk11-pchar 208 pk11-lib-manuf = "library-manufacturer" "=" *pk11-pchar 209 pk11-lib-desc = "library-description" "=" *pk11-pchar 210 pk11-lib-ver = "library-version" "=" 1*DIGIT *1("." 1*DIGIT) 211 pk11-object = "object" "=" *pk11-pchar 212 pk11-type = "type" "=" *1("public" / "private" / "cert" / 213 "secret-key" / "data") 214 pk11-id = "id" "=" *pk11-pchar 215 pk11-pin-source = "pin-source" "=" *pk11-qchar 216 pk11-pin-value = "pin-value" "=" *pk11-qchar 217 pk11-module-name = "module-name" = *pk11-qchar 218 pk11-module-path = "module-path" = *pk11-qchar 219 pk11-x-attr-nm-char = ALPHA / DIGIT / "-" / "_" 220 ; Permitted value of a vendor specific attribute is based on 221 ; whether the attribute is used in the path or in the query. 222 pk11-x-pattr = "x-" 1*pk11-x-attr-nm-char "=" *pk11-pchar 223 pk11-x-qattr = "x-" 1*pk11-x-attr-nm-char "=" *pk11-qchar 224 The URI path component contains attributes that identify a resource 225 in a one level hierarchy provided by Cryptoki producers. The query 226 component can contain a few attributes that may be needed to retrieve 227 the resource identified by the URI path. Both path and query 228 components may contain vendor specific attributes. Such attribute 229 names must start with an "x-" prefix. Attributes in the path 230 component are delimited by ';' character, attributes in the query 231 component use '&' as a delimiter. 233 The general '/' delimiter was removed from available characters that 234 do not have to be percent-encoded in the path component so that 235 generic URI parsers never split the path component into multiple 236 segments. The '/' delimiter can be used unencoded in the query 237 component. Delimiter '?' was removed since the PKCS#11 URI uses a 238 query component. Delimiter '#' was removed so that generic URI 239 parsers are not confused by unencoded hash characters. All other 240 generic delimiters are allowed to be used unencoded (':', '[', ']', 241 and '@') in the PKCS#11 URI. 243 The following table presents mapping between the PKCS#11 URI path 244 component attributes and the PKCS#11 API structure members and object 245 attributes. Given that PKCS#11 URI users may be quite ignorant about 246 the PKCS#11 specification the mapping is a product of a necessary 247 compromise between how precisely are the URI attribute names mapped 248 to the names in the specification and the ease of use and 249 understanding of the URI scheme. 251 +----------------------+---------------------+----------------------+ 252 | URI component path | Attribute | Attribute | 253 | attribute name | represents | corresponds in the | 254 | | | PKCS#11 | 255 | | | specification to | 256 +----------------------+---------------------+----------------------+ 257 +----------------------+---------------------+----------------------+ 258 | id | key identifier for | "CKA_ID" object | 259 | | object | attribute | 260 +----------------------+---------------------+----------------------+ 261 | library-description | character-string | "libraryDescription" | 262 | | description of the | member of CK_INFO | 263 | | library | structure | 264 +----------------------+---------------------+----------------------+ 265 | library-manufacturer | ID of the Cryptoki | "manufacturerID" | 266 | | library | member of the | 267 | | manufacturer | CK_INFO structure | 268 +----------------------+---------------------+----------------------+ 269 | library-version | Cryptoki library | "libraryVersion" | 270 | | version number | member of CK_INFO | 271 | | | structure | 272 +----------------------+---------------------+----------------------+ 273 | manufacturer | ID of the token | "manufacturerID" | 274 | | manufacturer | member of | 275 | | | CK_TOKEN_INFO | 276 | | | structure | 277 +----------------------+---------------------+----------------------+ 278 | model | token model | "model" member of | 279 | | | CK_TOKEN_INFO | 280 | | | structure | 281 +----------------------+---------------------+----------------------+ 282 | object | description (name) | "CKA_LABEL" object | 283 | | of the object | attribute | 284 +----------------------+---------------------+----------------------+ 285 | serial | character-string | "serialNumber" | 286 | | serial number of | member of | 287 | | the token | CK_TOKEN_INFO | 288 | | | structure | 289 +----------------------+---------------------+----------------------+ 290 | token | application-defined | "label" member of | 291 | | label, assigned | the CK_TOKEN_INFO | 292 | | during token | structure | 293 | | initialization | | 294 +----------------------+---------------------+----------------------+ 295 | type | object class (type) | "CKA_CLASS" object | 296 | | | attribute | 297 +----------------------+---------------------+----------------------+ 299 Table 1: Mapping between URI path component attributes and PKCS#11 300 specification names 302 The query component attribute "pin-source" specifies where the 303 application or library should find the normal user's token PIN, the 304 "pin-value" attribute provides the normal user's PIN value directly, 305 if needed, and the "module-name" and "module-path" attributes modify 306 default settings for accessing PKCS#11 providers. For the definition 307 of a "normal user", see [pkcs11_spec]. 309 The ABNF rules above is a best effort definition and this paragraph 310 specifies additional constraints. The PKCS#11 URI must not contain 311 duplicate attributes of the same name in the URI path component. It 312 means that each attribute may be present at most once in the PKCS#11 313 URI path. Aside from the query attributes defined in this document, 314 duplicate attributes may be present in the URI query component and it 315 is up to the URI consumer to decide on how to deal with such 316 duplicates. 318 It is recommended to percent-encode the whole value of the "id" 319 attribute which is supposed to be handled as arbitrary binary data. 321 The "library-version" attribute represents the major and minor 322 version number of the library and its format is "M.N". Both numbers 323 are one byte in size, see the "libraryVersion" member of the CK_INFO 324 structure in [pkcs11_spec] for more information. Value "M" for the 325 attribute must be interpreted as "M" for the major and "0" for the 326 minor version of the library. If the attribute is present the major 327 version number is mandatory. 329 An empty PKCS#11 URI path attribute that does allow for an empty 330 value matches a corresponding structure member or an object attribute 331 with an empty value. Note that according to the PKCS#11 332 specification [pkcs11_spec], empty character values in a PKCS#11 API 333 producer must be padded with spaces and should not be NULL 334 terminated. 336 3.4. PKCS#11 URI Scheme Query Attribute Semantics 338 An application may always ask for a PIN by any means it decides to. 339 What is more, in order not to limit PKCS#11 URI portability the "pin- 340 source" attribute value format and interpretation is left to be 341 implementation specific. However, we recommend the certain rules to 342 be followed in descending order for the value of the "pin-source" 343 attribute: 345 o if the value represents a local absolute path the implementation 346 should use it as a PIN file containing the PIN value 348 o if the value contains "|" the 349 implementation should read the PIN from the output of an 350 application specified with absolute path "". Note that character "|" representing a pipe does not have 352 to be percent encoded in the query component of the PKCS#11 URI. 354 o if the value represents a URI treat it as an object containing the 355 PIN. Such a URI may be "file:", "https:", another PKCS#11 URI, or 356 something else. 358 o interpret the value as needed in an implementation dependent way 360 If a URI contains both "pin-source" and "pin-value" query attributes 361 the URI should be refused as invalid. 363 Use of the "pin-value" attribute may have security related 364 consequences. Section 6 should be consulted before this attribute is 365 ever used. Standard percent encoding rules should be followed for 366 the attribute value. 368 A consumer of PKCS#11 URIs may modify default settings for accessing 369 a PKCS#11 provider or providers by accepting query component 370 attributes "module-name" and "module-path"." 372 Processing the URI query module attributes should follow these rules: 374 o attribute "module-name" is expected to contain a case-insensitive 375 PKCS#11 module name (not path nor filename) without system 376 specific affixes. Such affix could be an ".so" or ".DLL" suffix, 377 or a "lib" prefix, for example. Not using system specific affixes 378 is expected to increase portability of PKCS#11 URIs among 379 different systems. A URI consumer searching for PKCS#11 modules 380 is expected to use a system or application specific locations to 381 find modules based on the name provided in the attribute. 383 o attribute "module-path" is expected to contain a system specific 384 absolute path to the PKCS#11 module, or a system specific absolute 385 path to the directory of where PKCS#11 modules are located. 387 o the URI consumer may refuse to accept either of the attributes, or 388 both. If use of an attribute present in the URI string is not 389 accepted a warning message should be presented to the provider of 390 the URI. 392 o if either of the module attributes is present, only those modules 393 found matching these query attributes should be used to search for 394 an object represented by the URI. 396 o use of the module attributes does not suppress matching of any 397 other URI path component attributes present in a URI. 399 o semantics of using both attributes in the same URI string is 400 implementation specific but such use should be avoided. Attribute 401 "module-name" is preferred to "module-path" due to its system 402 independent nature but the latter may be more suitable for 403 development and debugging. 405 o a URI may not contain multiple module attributes of the same name. 407 Use of the module attributes may have security related consequences. 408 Section 6 should be consulted before these attribute are ever used. 410 A word "module" was chosen over word "library" in these query 411 attribute names to avoid confusion with semantically different 412 library attributes used in the URI path component. 414 3.5. PKCS#11 URI Matching Guidelines 416 The PKCS#11 URI can identify PKCS#11 storage objects, tokens, or 417 Cryptoki libraries. Note that since a URI may identify three 418 different types of entities the context within which the URI is used 419 may be needed to determine the type. For example, a URI with only 420 library attributes may either represent all objects in all tokens in 421 all Cryptoki libraries identified by the URI, all tokens in those 422 libraries, or just the libraries. 424 The following guidelines should help a PKCS#11 URI consumer (eg. an 425 application accepting PKCS#11 URIs) to match the URI with the desired 426 resource. 428 o the consumer must know whether the URI is to identify PKCS#11 429 storage object(s), token(s), or Cryptoki producer(s). 431 o if the consumer is willing to accept query component module 432 attributes only those PKCS#11 providers matching these attributes 433 should be worked with. See Section 3.4 for more information. 435 o an unrecognized attribute in the URI path component, including a 436 vendor specific attribute, should result in an empty set of 437 matched resources. The consumer should consider whether an error 438 message presented to the user is appropriate in such a case. 440 o an unrecognized attribute in the URI query should be ignored. The 441 consumer should consider whether a warning message presented to 442 the user is appropriate in such a case. 444 o an attribute not present in the URI path but known to a consumer 445 matches everything. Each additional attribute present in the URI 446 path further restricts the selection. 448 o a logical extension of the above is that an empty URI path matches 449 everything. For example, if used to identify storage objects it 450 matches all accessible objects in all tokens provided by all 451 PKCS#11 API producers found in the system. 453 o use of PIN attributes may change the set of storage objects 454 visible to the consumer. 456 o in addition to query component attributes defined in this 457 document, vendor specific query attributes may contain further 458 information about how to perform the selection or other related 459 information. 461 3.6. PKCS#11 URI Comparison 463 Comparison of two URIs is a way of determining whether the URIs are 464 equivalent without comparing the actual resource the URIs point to. 465 The comparison of URIs aims to minimize false negatives while 466 strictly avoiding false positives. 468 Two PKCS#11 URIs are said to be equal if URIs as character strings 469 are identical as specified in Section 6.2.1 of [RFC3986], or if both 470 following rules are fulfilled: 472 o set of attributes present in the URI is equal. Note that the 473 ordering of attributes in the URI string is not significant for 474 the mechanism of comparison. 476 o values of respective attributes are equal based on rules specified 477 below 479 The rules for comparing values of respective attributes are: 481 o values of path component attributes "library-description", 482 "library-manufacturer", "manufacturer", "model", "object", 483 "serial", "token", "type", and query component attribute "module- 484 name" must be compared using a simple string comparison as 485 specified in Section 6.2.1 of [RFC3986] after the case and the 486 percent-encoding normalization are both applied as specified in 487 Section 6.2.2 of [RFC3986]. 489 o value of attribute "id" must be compared using the simple string 490 comparison after all bytes are percent-encoded using uppercase 491 letters for digits A-F. 493 o value of "pin-source", if deemed containing the filename with the 494 PIN value, must be compared using the simple string comparison 495 after the full syntax based normalization as specified in 496 Section 6.2.2 of [RFC3986] is applied. If value of the "pin- 497 source" attribute is believed to be overloaded it is recommended 498 to perform case and percent-encoding normalization before the 499 values are compared but the exact mechanism of comparison is left 500 to the application. 502 o value of attribute "module-path" must be compared using the simple 503 string comparison after the full syntax based normalization as 504 specified in Section 6.2.2 of [RFC3986] is applied. 506 o value of attribute "library-version" must be processed as a 507 specific scheme-based normalization permitted by Section 6.2.3 of 508 [RFC3986]. The value must be split into a major and minor version 509 with character '.' (dot) serving as a delimiter. Library version 510 "M" must be treated as "M" for the major version and "0" for the 511 minor version. Resulting minor and major version numbers must be 512 then separately compared numerically. 514 o when comparing vendor specific attributes it is recommended to 515 perform case and percent-encoding normalization before the values 516 are compared but the exact mechanism of comparison is left to the 517 application. 519 4. Examples of PKCS#11 URIs 521 This section contains some examples of how PKCS#11 token objects, 522 PKCS#11 tokens, and PKCS#11 libraries can be identified using the 523 PKCS#11 URI scheme. Note that in some of the following examples, 524 newlines and spaces were inserted for better readability. As 525 specified in Appendix C of [RFC3986], whitespace should be ignored 526 when extracting the URI. Also note that all spaces as part of the 527 URI are percent-encoded, as specified in Appendix A of [RFC3986]. 529 An empty PKCS#11 URI might be useful to PKCS#11 consumers. See 530 Section 3.5 for more information on semantics of such a URI. 532 pkcs11: 534 One of the simplest and most useful forms might be a PKCS#11 URI that 535 specifies only an object label and its type. The default token is 536 used so the URI does not specify it. Note that when specifying 537 public objects, a token PIN might not be required. 539 pkcs11:object=my-pubkey;type=public 541 When a private key is specified either the "pin-source" attribute, 542 "pin-value, or an application specific method would be usually used. 543 Note that '/' is not percent-encoded in the "pin-source" attribute 544 value since this attribute is part of the query component, not the 545 path, and thus is separated by '?' from the rest of the URI. 547 pkcs11:object=my-key;type=private?pin-source=/etc/token 549 The following example identifies a certificate in the software token. 550 Note an empty value for the attribute "serial". Also note that the 551 "id" attribute value is entirely percent-encoded, as recommended. 552 While ',' is in the reserved set it does not have to be percent- 553 encoded since it does not conflict with any sub-delimiters used. The 554 '#' character as in "The Software PKCS#11 Softtoken" must be percent- 555 encoded. 557 pkcs11:token=The%20Software%20PKCS%2311%20Softtoken; 558 manufacturer=Snake%20Oil,%20Inc.; 559 model=1.0; 560 object=my-certificate; 561 type=cert; 562 id=%69%95%3E%5C%F4%BD%EC%91; 563 serial= 564 ?pin-source=/etc/token_pin 566 The next example covers how to use the "module-name" query attribute. 567 Considering that the module is located in /usr/lib/libmypkcs11.so.1 568 file, the attribute value is "mypkcs11", ie. only the module name 569 without the full path, and without the platform specific "lib" prefix 570 and ".so.1" suffix. 572 pkcs11:object=my-sign-key; 573 type=private 574 ?module-name=mypkcs11 576 The following example covers how to use the "module-path" query 577 attribute. The attribute may be useful if a user needs to provide 578 the key via a PKCS#11 module stored on a removable media, for 579 example. 581 pkcs11:object=my-sign-key; 582 type=private 583 ?module-path=/mnt/libmypkcs11.so.1 585 In the context where a token is expected the token can be identified 586 without specifying any PKCS#11 objects. A PIN might still be needed 587 in the context of listing all objects in the token, for example. 588 Section 6 should be consulted before the "pin-value" attribute is 589 ever used. 591 pkcs11:token=Software%20PKCS%2311%20softtoken; 592 manufacturer=Snake%20Oil,%20Inc. 593 ?pin-value=the-pin 595 The Cryptoki library alone can be also identified without specifying 596 a PKCS#11 token or object. 598 pkcs11:library-manufacturer=Snake%20Oil,%20Inc.; 599 library-description=Soft%20Token%20Library; 600 library-version=1.23 602 The following example shows that the attribute value can contain a 603 semicolon. In such case, it is percent-encoded. The token attribute 604 value must be read as "My token; created by Joe". Lower case letters 605 can also be used in percent-encoding as shown below in the "id" 606 attribute value but note that Sections 2.1 and 6.2.2.1 of [RFC3986] 607 read that all percent-encoded characters should use the uppercase 608 hexadecimal digits. More specifically, if the URI string was to be 609 compared, the algorithm defined in Section 3.6 explicitly requires 610 percent-encoding to use the uppercase digits A-F in the "id" 611 attribute values. And as explained in Section 3.3, library version 612 "3" should be interpreted as "3" for the major and "0" for the minor 613 version of the library. 615 pkcs11:token=My%20token%25%20created%20by%20Joe; 616 library-version=3; 617 id=%01%02%03%Ba%dd%Ca%fe%04%05%06 619 If there is any need to include literal "%;" substring, for example, 620 both characters must be escaped. The token value must be read as "A 621 name with a substring %;". 623 pkcs11:token=A%20name%20with%20a%20substring%20%25%3B; 624 object=my-certificate; 625 type=cert 626 ?pin-source=/etc/token_pin 628 The next example includes a small A with acute in the token name. It 629 must be encoded in octets according to the UTF-8 character encoding 630 and then percent-encoded. Given that a small A with acute is U+225 631 unicode code point, the UTF-8 encoding is 195 161 in decimal, and 632 that is "%C3%A1" in percent-encoding. 634 pkcs11:token=Name%20with%20a%20small%20A%20with%20acute:%20%C3%A1; 635 object=my-certificate; 636 type=cert 638 Both the path and query components may contain vendor specific 639 attributes. Attributes in the query component may be delimited by 640 either ';' or '&'. We use '&' in the example that follows. 642 pkcs11:token=my-token; 643 object=my-certificate; 644 type=cert; 645 x-vend-aaa=value-a 646 ?pin-source=/etc/token_pin& 647 x-vend-bbb=value-b 649 5. IANA Considerations 651 This document moves the "pkcs11" URI scheme from the provisional to 652 the permanent URI scheme registry. The registration template for the 653 URI scheme is accessible on http://www.iana.org/assignments/uri- 654 schemes. 656 6. Security Considerations 658 There are general security considerations for URI schemes discussed 659 in Section 7 of [RFC3986]. 661 From those security considerations, Section 7.1 of [RFC3986] applies 662 since there is no guarantee that the same PKCS#11 URI will always 663 identify the same object, token, or a library in the future. 665 Section 7.2 of [RFC3986] applies since by accepting query component 666 attributes "module-name" or "module-path" the consumer potentially 667 allows loading of arbitrary code into a process. 669 Section 7.5 of [RFC3986] applies since the PKCS#11 URI may be used in 670 world readable command line arguments to run applications, stored in 671 public configuration files, or otherwise used in clear text. For 672 that reason the "pin-value" attribute should only be used if the URI 673 string itself is protected with the same level of security as the 674 token PIN by itself otherwise is. 676 7. References 678 7.1. Normative References 680 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 681 10646", RFC 3629, STD 63, November 2003. 683 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 684 Resource Identifier (URI): Generic Syntax", RFC 3986, STD 685 66, January 2005. 687 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 688 Specifications: ABNF", RFC 5234, STD 68, January 2008. 690 7.2. Informative References 692 [RFC4395] Hansen, T., Hardie, T., and L. Masinter, "Guidelines and 693 Registration Procedures for New URI Schemes", RFC 4395, 694 February 2006. 696 [pkcs11_spec] 697 RSA Laboratories, "PKCS #11: Cryptographic Token Interface 698 Standard v2.20", June 2004. 700 Authors' Addresses 702 Jan Pechanec 703 Oracle Corporation 704 4180 Network Circle 705 Santa Clara CA 95054 706 USA 708 Email: Jan.Pechanec@Oracle.COM 709 URI: http://www.oracle.com 711 Darren J. Moffat 712 Oracle Corporation 713 Oracle Parkway 714 Thames Valley Park 715 Reading RG6 1RA 716 UK 718 Email: Darren.Moffat@Oracle.COM 719 URI: http://www.oracle.com