PKIX Working Group J. H. Yoon (KISA) Internet Draft C. J. Chung (KISA) expires May, 2002 Y. Lee (KISA) J. I. Lee (KISA) November, 2001 Wireless Internet X.509 Public Key Infrastructure Certificate Management Protocols Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract This document describes the X.509 Public Key Infrastructure(PKI) Certificate Management Protocols(CMP) in wireless internet environment. Protocol messages are defined for all relevant aspects of certificate creation and management. Note that "certificate" in this document refers to an X.509v3 Certificate as defined in [ITUTX509]. Yoon, Chung, Lee Expires May. 2002 [Page 1] Internet Draft Nov 2001 1. Introduction Differring from wired system terminal, wirelss one has many limitations in CPU, memory, battery life, and a user interface. Moreover the wireless network has very low bandwith, latency, and data loss. For that reasons, using PKCS#10 or CMP(RFC2510) is difficult in wireless environment. Actually the problem comes from ASN.1 encoding. Some big modules, like ASN.1 (compilier) and LDAP etc., can not be uploaded at mobile terminals. So new format and protocol in certificate request are needed. This document describes wireless cerfificate management protocols using signText function[WAPscriptCrypto] defined in WAP specification. 1.1 Protocol requirements Construction of a certification request involves the following steps: a) A SignedContent(Certificate Request) value is constructed. This value may include the public key, a portion of the end-entity's (EE's) ID and password, nonce. Other requested certificate fields, and additional control information related to the registration process are made in off-line. b) A proof of possession (of the private key corresponding to the public key for which a certificate is being requested) value may be calculated across the SignedContent value. c) The CR(Certificate Request) message is securely communicated to a CA. However the specific methods of secure transport are beyond the scope of this document. 1.2 Terminology The key words "MUST", "REQUIRED", "SHOULD", "RECOMMENDED", and "MAY" in this document (in uppercase, as shown) are to be interpreted as described in RFC 2119. The following abbreviations are used in this document. A) CA: Certification Authority B) CRL: Certificate Revocation List C) CMP: Certificate Management Protocol D) DN: Distinguished Name E) DER: Distinguished Encoding Rules Yoon, Chung, Lee Expires May. 2002 [Page 2] Internet Draft Nov 2001 F) LDAP: Lightweight Directory Access Protocol G) POP: Proof of Possession H) PEM: Privacy Enhanced Mail I) RA: Registration Authority J) CN: Common Name 2. Certificate management protocol When reissue, renewal, suspension, or revocation of a subscriber's certificate is requested, the signText function defined in WAP is used to generate the request format. 2.1 Certificate reissuing request 2.1.1 Overview Certificate reissuing request format is created when the subscriber believes that the digital signature generation key is lost, damaged, stolen, or leaked, and transmit it to the certification authority (or the registration authority). 2.1.2 Configuration of certificate reissue request format The subscriber MUST generate POP method, certificate reissue request format including the public keys, and configure a request format that can prevent Replay attack, message counterfeiting and forgery, and ensures confidentiality, and deliver the certificate reissue request format to a certification authority (or a registration authority). 2.1.3 Structure of certificate reissue request format ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Subscriber | | RA (or CA) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ CR = SignedContent | CR | | ----------> | | | SignedContent = CR ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ M = type|PK_new|ID_new N = Password H(M,N) [See RFC2104] SignedContent = signText(M|H(M,N), 1, 0, í—í˜) [See Appendix B] Yoon, Chung, Lee Expires May. 2002 [Page 3] Internet Draft Nov 2001 "type" : Type string value of management type (digital signature: 210) PK_new: new digital signature verification key of subscriber [See appendix D] ID_new: new reference number of subscriber Password: authorization code of subscriber As the option of signText is set at 1, PK (public key) and ID are extracted from M among signed messages. RA(or CA) MUST verify SignedContent by means of PK (public key). (POP verification process [RFC2510]) RA (or CA) retrieves the Password corresponding to ID from its database, and composes N. Then, RA (or CA) calculates H(M,N), where the M is in the Subscriber's signed CR message. And RA (or CA) compares calculated value with subscriber's hash value which is in the Subscriber's signed CR message. (user authentication) 2.2 Certificate renewal request 2.2.1Overview The certificate update request is to configure and create the certificate renewal request format before the expiry date, and submit it to the certification authority (or the registration authority). 2.2.2 Configuration of certificate renewal request format Renewal can be done with or without key replacement. In these cases, the update request format must be created and sent to the certification authority (or the registration authority). 2.2.3 Structure of certificate update request format Yoon, Chung, Lee Expires May. 2002 [Page 4] Internet Draft Nov 2001 o Case1. No key replacement ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Subscriber | | RA (or CA) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | nonce | nonce generated | <---------- | CR = SignedContent | CR | | ----------> | | | SignedContent = CR ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ M = type|CN string in owner's DN N = nonce(replay attack prevention) SignedContent = signText(M|N, 5, 1, H(public key)) "type" : Type string value of management type (digital signature: 310) PK: digital signature verification key of subscriber H(public key) : hash value for subscriber's existing public key nonce : UTC time generated by server As the option of signText is set at 5, the existing certificate must be brought along with the PK of the existing certificate. Verify SignedContent by means of PK(public key).(user verification process) Here, the CN string in subscriber's DN is an option, and can have a null value. (including the vertical line ( | )). The "type" string must be included. o Case2. Key replacement ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Subscriber | | RA (or CA) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | nonce | nonce generated | <---------- | CR = SignedContent | CR | | ----------> | | | SignedContent = CR ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ M = type|PK Generate SignValue with nonce signed by SK_new distribution N = nonce|SignValue SignedContent = signText(M|N, 5, 1, H(public key)) Yoon, Chung, Lee Expires May. 2002 [Page 5] Internet Draft Nov 2001 "type" : Type string value of management type (digital signature: 410) PK: digital signature verification key of subscriber PK_new : subscriberí¯s new digital signature verification key SK_new : subscriberí¯s digital signature generation key H(public key) : hash value for subscriber's existing public key nonce : UTC time generated by server As the option of signText is set at 5, the existing certificate must be brought along with the PK of the existing certificate. Verify SignedContent by means of PK(public key).(user verification process) N is verified by the signed message M (POP verification regarding new public key) 2.3 Certificate suspension request 2.3.1 Overview The suspension request format is created when the subscriber suspects that his generation key has been lost, damaged, stolen, or leaked. 2.3.2 Configuration of certificate suspension request format The subscriber must configure the certificate suspension request format capable of preventing user certification and replay attack, and submit it to the certification authority (or the registration authority). 2.3.3 Structure of certificate suspension request format ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Subscriber | | RA (or CA) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | nonce | nonce generated | <---------- | CR = SignedContent | CR | | ----------> | | | SignedContent = CR ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ M = type|CertificateHold N = nonce(replay attack prevention) SignedContent = signText(M|N, 5, 1, H(public key)) Yoon, Chung, Lee Expires May. 2002 [Page 6] Internet Draft Nov 2001 "type" : Type string value of management type (digital signature: 510) PK: digital signature verification key of subscriber H(public key) : hash value for subscriber's digital signature verification key nonce : UTC time generated by server As the option of signText is set at 5, the existing certificate must be brought along with the PK of the existing certificate. Verify SignedContent by means of PK(public key) (user verification process). The reason for suspension is checked through signed message M. As the option of SignText is set at 5, the existing certificate is added to the suspension list. 2.4 Certificate revocation request 2.4.1 Overview When the subscriber applied for certificate revocation, or it is suspected that the subscriberí¯s generation key is lost, damaged, stolen, or leaked, the subscriber must create the revocation request format, and submit it to the certification authority (or the registration authority). 2.4.2 Configuration of certificate revocation request format If the subscriberí¯s generation key is lost or damaged, the subscriber must visit the certification authority (or the registration authority) in person, and apply for revocation. If revocation has been applied for because it is suspected that the subscriberí¯s generation key was stolen or leaked, the subscriber must create the revocation request format via online, and submit it to certification authority (or the registration authority). 2.4.3 Structure of certificate revocation request format ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Subscriber | | RA (or CA) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | nonce | nonce generated | <---------- | CR = SignedContent | CR | | ----------> | | | SignedContent = CR ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Yoon, Chung, Lee Expires May. 2002 [Page 7] Internet Draft Nov 2001 M = type|ReasonCode SignedContent = signText(M, 5, 1, H(public key)) "type" : Type string value of management type (digital signature: 610) PK: digital signature verification key of subscriber H(public server) : hash value for subscriber's digital signature verification key nonce : UTC time generated by server As the option of signText is set at 5, the existing certificate must be brought along with the PK of the existing certificate. Verify SignedContent by means of PK(public key) (user verification process). The reason for revocation is checked through signed message M. As the option of SignText is set at 5, the existing certificate is added to the revocation list. 3. References [WAP211] Forum Proposed Version 9-Mar-2000, WAP-211-X.509: WAP Certificate and CRL Profile [WAP217] WAP Forum Proposed Version 3-Mar-2000, WAP-217-WPKI: Wireless Application Protocol Public Key Infrastructure Definition [WAPe2e] WAP Forum Approved Version 11-July-2000, WAPTM Transport Layer E2E Security Document [WAPscriptCrypto] WAP Forum Proposed Version 05-Nov-1999, WMLScript Crypto Library [WAP261] WAP Forum Approved Version 06-April-2001, Wireless Transport Layer Security [RFC2104] H. Krawczyk, M. Bellare,R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", February 1997. [RFC1521] N. Borenstein, N. Freed, "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies", September 1993. [RFC2560] M. Myers, R. Ankney, A. Malpani, S. Galperin, C. Adams, "X.509 Internet Public Key Infrastructure Online Certificate Yoon, Chung, Lee Expires May. 2002 [Page 8] Internet Draft Nov 2001 Status Protocols", June 1999. [RFC2510] C. Adams, S. Farrell, "Internet X.5.09 Public Key Infrastructure Certificate Management Protocols", March 1999 [RFC2511] M. Myers, C. Adams, D. Solo, D. Kemp, "Internet X.5.09 Certificate Request Message Format", March 1999 [ITUTX509] ITU-T Recommendation X.509(1997), Information technology - Open System Interconnection - The Directory : Authentication Framework [RFC2459] R. Housley, W. Ford, W. Polk, D. Solo, "Internet X.509 Public Key Infrastructure Certificate and CRL Profile", January 1999 [PKCS10] RSA Laboratories, "PKCS#10, Certification Request Syntax Format", 1999. [PKCS12]RSA Laboratories, "PKCS#12, Personal Information Exchange Standard", 1999. 4. Intellectual Property Rights The IETF has been notified of intellectual property rights claimed in regard to some or all of the specification contained in this document. For more information consult the online list of claimed rights (see http://www.ietf.org/ipr.html). The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementors or users of this specification can be obtained from the IETF Secretariat. Yoon, Chung, Lee Expires May. 2002 [Page 9] Internet Draft Nov 2001 Appendix A. Definition of management type string, and encoding & decoding rules íš Definition of management type string ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Type| Encryption & digital signature | Digital signature | Encryption ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Request | 100 110 120 Re-issuing | 200 210 220 Renewal | 300 310 320 Update (key) | 400 410 420 Suspension | 500 510 520 Revocation | 600 610 620 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ type = 3byte(string) & req = Base64 encoded(string) : POST mode is used. íš Encoding & Decoding rules - In this document, all binary data MUST comply with the base64 encoding rules. - The vertical line (|) is used as the separator, but it will not be used for hash message concatenation. - The vertical line (|) will be excluded from the range of characters that can be used as reference numbers (ID). - The maximum length of the reference number is 10 characters, and it is alphanumeric and case-sensitive. - The maximum length of the authorization code is 30 characters, and it is alphanumeric and case-sensitive. - The minimum length of the authorization code varies depending on the period. +++++++++++++++++++++++++++ Period Length +++++++++++++++++++++++++++ 1 day 12 characters 3 days 13 characters 1 week 14 characters 10 days 14 characters 2 weeks 15 characters 1 month 16 characters +++++++++++++++++++++++++++ íÛ In case that ECDSA key is 20 bytes long, and the reference Yoon, Chung, Lee Expires May. 2002 [Page 10] Internet Draft Nov 2001 number is 8 bytes long Appendix B. SignText function [WAPscriptCrypto] B.1 SignText configuration signedString = Crypto.signText(StringToSign, options, keyIdType, keyId) B.2 Parameters íñstringToSign = String : contents of actual message íñoptions = Integer : OR operation of several optional values is possible. +++++++++++++++++++++++++++++++++++++++++++++++++ value description +++++++++++++++++++++++++++++++++++++++++++++++++ 0x0001 INCLUDE_CONTENT: Information is transferred. Return value includes StringToSign. 0x0002 INCLUDE_KEY_HASH: Return value includes the public key hash value corresponding to the signature key. 0x0004 INCLUDE_CERTIFICATE: Return value includes the certificate or the URL of the certificate. If the Browser cannot obtain the certificate, í—error:noCert" value must be returned. +++++++++++++++++++++++++++++++++++++++++++++++++ íñKeyIdType = Integer ++++++++++++++++++++++++++++++++++++++++++++++++ value description ++++++++++++++++++++++++++++++++++++++++++++++++ 0 None:Used when Key Identifier is not used. 1 User_Key_HASH: User public key hash value is offered to the next parameter (keyId). 2 TRUSTED_Key_HASH: The public key hash value of the Trusted CA is offered to the next parameter (keyId). ++++++++++++++++++++++++++++++++++++++++++++++++ Yoon, Chung, Lee Expires May. 2002 [Page 11] Internet Draft Nov 2001 íñkeyId = String : Hash value defined in accordance with KeyIdType. For instance, SHA-1 public key hash value is 20 bytes. B.3 Return value íñReturn value = String or Invalid : If the return value is without errors, it is the base-64 [RFC1521] encoding of SignedContent. Appendix C. Response to certification request format C.1 Success íš MIME Type : application/vnd.wap.cert-response íš Content : Base64-encoded CertResponse enum { cert_info(0), cert(1), referral(2), (255) } CertRespType; struct { CharacterSet character_set; opaque displayName <1 .. 2^8 - 1>; } CertDisplayName; struct { opaque url <0 .. 128>; } UrlPoint; struct { unit8 version; CertRespType type; select (type) { case cert_info: CertDisplayName display_name; Identifier ca_domain; UrlPoint url; case cert: CertDisplayName display_name; Identifier ca_domain; X509Certificate cert; case referral: Yoon, Chung, Lee Expires May. 2002 [Page 12] Internet Draft Nov 2001 UrlPoint url; unit32 seconds_to_wait; } } CertResponse; C.2 Fail íš MIME Type : text/plain íš Content : Error message of ascii text value Appendix D. Structure of PK(Public Key) enum { rsa(2), ecdh(3), ecdsa(4), (255) } PublicKeyType ; struct { PublicKeyType publicKeyType; select (publicKeyType) { case ecdh : ECPublicKey ; case ecdsa : ECPublicKey ; case rsa : RSAPublicKey ; } ; } PublicKey ; struct { opaque url <0 .. 128>; } UrlPoint; struct { opaque rsa_exponent<1..2^16-1> ; opaque rsa_modulus<1..2^16-1> ; } RSAPublicKey ; enum { ECunNamed(0), ECNamed(1), implicitlyCA(2), (255) } ECNameType; struct { ECNameType ecNameType; select (ecNameType) { Yoon, Chung, Lee Expires May. 2002 [Page 13] Internet Draft Nov 2001 case ECunNamed : ECParameters ecParameters; case ECNamed : opaque oid<1..2^8-1> ; case implicitlyCA : struct { }; } ; opaque public_key_point<1..2^8-1> ; } ECPublicKey ; enum { ec_prime_p(1), ec_characteristic_two(2), (255) } ECFieldID; enum { ec_basis_onb(1), ec_basis_trinomial(2), ec_basis_pentanomial(3), ec_basis_polynomial(4) } ECBasisType; struct { opaque a <1..2^8-1>; opaque b <1..2^8-1>; opaque seed <0..2^8-1>; } ECCurve; struct { ECFieldID field; select (field) { case ec_prime_p: opaque prime_p <1..2^8-1>; case ec_characteristic_two: uint16 m; ECBasisType basis; select (basis) { case ec_basis_onb: struct { }; case ec_trinomial: uint16 k; case ec_pentanomial: uint16 k1; uint16 k2; uint16 k3; case ec_basis_polynomial: opaque irreducible <1..2^8-1> }; }; ECCurve curve; ECPoint base; Yoon, Chung, Lee Expires May. 2002 [Page 14] Internet Draft Nov 2001 opaque order <1..2^8-1>; opaque cofactor <1..2^8-1>; } ECParameters; Appendix E. Author Addresses: Jaeil Lee 78, Garak-dong, Songpa-Gu, Seoul, Korea, 138-803 Korea Information Security Agency E-Mail: jilee@kisa.or.kr Young Lee Korea Information Security Agency E-Mail: ylee@kisa.or.kr Chanju Chung Korea Information Security Agency E-Mail: cjchung@kisa.or.kr Jaeho Yoon Korea Information Security Agency E-Mail: jhyoon@kisa.or.kr Yoon, Chung, Lee Expires May. 2002 [Page 15]