PKIX WG Sean Turner, IECA Internet Draft Daniel Brown, Certicom Intended Status: Standard Track Kelvin Yiu, Microsoft Updates: 3279 (once approved) Russ Housley, Vigil Security Expires: January 11, 2009 Tim Polk, NIST July 11, 2008 Elliptic Curve Cryptography Subject Public Key Information draft-ietf-pkix-ecc-subpubkeyinfo-06.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 This Internet-Draft will expire on January 11, 2009. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document specifies the syntax and semantics for the Subject Public Key Information field in certificates that support Elliptic Curve Cryptography. This document updates RFC 3279. Turner, et al Expires January 11, 2009 [Page 1] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Table of Contents 1. Introduction...................................................2 1.1. Terminology...............................................3 2. Subject Public Key Information Fields..........................3 2.1. Elliptic Curve Cryptography Public Key Algorithm Identifiers...............................................4 2.1.1. Unrestricted Identifiers and Parameters..............5 2.1.1.1. Named Curve.....................................6 2.1.1.2. Specified Curve.................................8 2.1.1.2.1. Specified Curve Version....................9 2.1.1.2.2. Field Identifiers..........................9 2.1.1.2.2.1. Prime-p..............................10 2.1.1.2.2.2. Characteristic-two...................10 2.1.1.2.3. Curve.....................................12 2.1.1.2.4. Base......................................13 2.1.1.2.5. Hash......................................13 2.1.2. Restricted Algorithm Identifiers and Parameters.....15 2.2. Subject Public Key.......................................16 3. Key Usage Bits................................................16 4. Security Considerations.......................................17 5. IANA Considerations...........................................19 6. Acknowledgements..............................................19 7. References....................................................19 7.1. Normative References.....................................19 7.2. Informative References...................................20 Appendix A. ASN.1 Modules........................................21 Appendix A.1. 1988 ASN.1 Module...............................21 Appendix A.2. 2004 ASN.1 Module...............................29 Appendix B. Random Base Generation Routine.......................40 Appendix B.1. Generation of Random Candidate Point............40 Appendix B.2. Generation of Random Base.......................41 1. Introduction This document specifies the format of the subjectPublicKeyInfo field in X.509 certificates [RFC5280] that use Elliptic Curve Cryptography (ECC). It updates [RFC3279]. This document specifies the encoding formats for public keys used with the following ECC algorithms: Elliptic Curve Digital Signature Algorithm (ECDSA); Elliptic Curve Diffie-Hellman (ECDH) family schemes; and, Elliptic Curve Menezes-Qu-Vanstone (ECMQV) family schemes. Turner, et al Expires January 11, 2009 [Page 2] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Two methods for specifying the algorithms that can be used with the subjectPublicKey are defined. One method does not restrict the algorithms the key can be used with while the other method does restrict the algorithms the key can be used with. To promote interoperability, this document indicates which is required to implement. Three methods for specifying the algorithm's parameters are also defined. One allows for complete specification of the Elliptic Curve (EC), one allows for the EC to be identified by an object identifier, and one allows for the EC to be inherited from the issuer's certificate. To promote interoperability, this document indicates which options are required to implement. Specification of all EC parameters is complicated with many options. To promote interoperability, this document indicates which options are required to implement. 1.1. Terminology 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. Subject Public Key Information Fields In the X.509 certificate, the subjectPublicKeyInfo field has the SubjectPublicKeyInfo type, which has the following ASN.1 syntax: SubjectPublicKeyInfo ::= SEQUENCE { algorithm AlgorithmIdentifier {{PKAlgorithms}}, subjectPublicKey BIT STRING } The fields in SubjectPublicKeyInfo have the following meanings: algorithm is the algorithm identifier and algorithm parameters for the ECC public key. See paragraph 2.1. subjectPublicKey is the ECC public key. See paragraph 2.2. Turner, et al Expires January 11, 2009 [Page 3] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 The class ALGORITHM parameterizes the AlgorithmIdentifier type with sets of legal values (this class is used in many places in this document): ALGORITHM ::= CLASS { &id OBJECT IDENTIFIER UNIQUE, &Type OPTIONAL } WITH SYNTAX { OID &id [PARMS &Type] } The type AlgorithmIdentifier is parameterized to allow legal sets of values to be specified by constraining the type with an information object set. There are two parameterized types for AlgorithmIdentifier defined in this document: PKAlgorithms (see paragraph 2.1) and CurveHashFunctions (see paragraph 2.1.1.2.5). AlgorithmIdentifier {ALGORITHM:IOSet} ::= SEQUENCE { algorithm ALGORITHM.&id({IOSet}), parameters ALGORITHM.&Type({IOSet}{@algorithm}) OPTIONAL } The fields in AlgorithmIdentifier have the following meaning: algorithm identifies a cryptographic algorithm. The OBJECT IDENTIFIER component identifies the algorithm. The contents of the optional parameters field will vary according to the algorithm identified. parameters, which is OPTIONAL, varies based on the algorithm identified. 2.1. Elliptic Curve Cryptography Public Key Algorithm Identifiers The algorithm field in the SubjectPublicKeyInfo structure indicates the algorithms and any associated parameters for the ECC public key (see paragraph 2.2). The algorithms are restricted to the PKAlgorithms parameterized type, which uses the following ASN.1 structure: PKAlgorithms ALGORITHM ::= { pk-ec | pk-ecDH | pk-ecMQV, ... -- Extensible } Turner, et al Expires January 11, 2009 [Page 4] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 The algorithms defined are as follows: pk-ec indicates that the algorithms that can be used with the subject public key are not restricted (i.e., they are unrestricted). The key is only restricted by the values indicated in the key usage certificate extension. The pk-ec CHOICE MUST be supported. See paragraph 2.1.1. This value is also used when a key is used with ECDSA. pk-ecDH and pk-ecMQV MAY be supported. See paragraph 2.1.2. 2.1.1. Unrestricted Identifiers and Parameters The "unrestricted" algorithm is defined as follows: pk-ec ALGORITHM ::= { OID id-ecPublicKey PARMS ECParameters } The algorithm identifier is: id-ecPublicKey OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 } The parameters for id-ecPublicKey are as follows and they MUST always be present: ECParameters ::= CHOICE { namedCurve CURVE.&id({NamedCurve}), specifiedCurve SpecifiedCurve, implicitCurve NULL } The fields in ECParameters have the following meanings: namedCurve allows all the required values for a particular set of elliptic curve domain parameters to be represented by an object identifier. This choice MUST be supported. See paragraph 2.1.1.1. specifiedCurve allows all of the required values to be explicitly specified. This choice MAY be supported, and if it is, implicitCurve MUST also be supported. See paragraph 2.1.1.2. implicitCurve allows the elliptic curve parameters to be inherited from the issuer's certificate. This choice MAY be supported, but if subordinate certificates use the same namedCurve as their superior, then the subordinate certificate Turner, et al Expires January 11, 2009 [Page 5] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 MUST use the namedCurve option. That is, implicitCurve is only supported if the superior doesn't use the namedCurve option. 2.1.1.1. Named Curve The namedCurve field in ECParameters uses the class CURVE to constrain the set of legal values from NamedCurve, which are object identifiers: CURVE ::= CLASS { &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { ID &id } The NamedCurve parameterized type is defined as follows: NamedCurve CURVE ::= { { ID secp192r1 } | { ID sect163k1 } | { ID sect163r2 } | { ID secp224r1 } | { ID sect233k1 } | { ID sect233r1 } | { ID secp256r1 } | { ID sect283k1 } | { ID sect283r1 } | { ID secp384r1 } | { ID sect409k1 } | { ID sect409r1 } | { ID secp521r1 } | { ID sect571k1 } | { ID sect571r1 }, ... -- Extensible } The curve identifiers are the fifteen NIST recommended curves: -- Note in [ANSIX9.62] the curves are referred to as 'ansiX9' as -- opposed to 'sec'. For example secp192r1 is the same curve as -- ansix9p192r1. -- Note that in [RFC3279] the secp192r1 curve was referred to as -- prime192v1 and the secp256v1 curve was referred to as secp256r1. -- Note that [DSS] refers to secp192r1 as P-192, secp224r1 as P-224, -- secp384r1 as P-384, secp521r1 as P-521. secp192r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 1 } sect163k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 1 } sect163r2 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 15 } secp224r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 33 } Turner, et al Expires January 11, 2009 [Page 6] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 sect233k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 26 } sect233r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 27 } secp256r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 7 } sect283k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 16 } sect283r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 17 } secp384r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 34 } sect409k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 36 } sect409r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 37 } secp521r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 35 } sect571k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 38 } sect571r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 39 } Turner, et al Expires January 11, 2009 [Page 7] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 2.1.1.2. Specified Curve The specifiedCurve field in ECParameters is of SpecifiedCurve type. SpecifiedCurve uses the following ASN.1 structure: SpecifiedCurve ::= SEQUENCE { version SpecifiedCurveVersion ( ecpVer1 | ecpVer2 | ecpVer3, ... ), fieldID FieldID {{FieldTypes}}, curve Curve, -- Curve E base ECPoint, -- Base point G order INTEGER, -- Order n of the base point cofactor INTEGER OPTIONAL, -- The integer h = #E(Fq)/n hash HashAlgorithm OPTIONAL, ... -- Extensible } The fields in SpecifiedCurve have the following meaning: version specifies the version number of the elliptic curve parameters. See paragraph 2.1.1.2.1. fieldID identifies the finite field over which the elliptic curve, specified in the curve field, is defined. See paragraph 2.1.1.2.2. curve specifies the elliptic curve E. See paragraph 2.1.1.2.3. base specifies the base point G on the elliptic curve E, specified in the curve field. See paragraph 2.1.1.2.4. order specifies the order n of the base point G, specified in base. cofactor is the order of the curve, specified in the curve field, divided by the order, specified in the order field, of the base point, specified in the base field (i.e., h = #E(Fq)/n). Inclusion of the cofactor is optional; however, it is strongly RECOMMENDED that the cofactor be included in order to facilitate interoperability between implementations. hash is the hash algorithm used to generate the elliptic curve E, specified in the curve field, and/or base point G, specified in the base field, verifiably pseudorandom. If the hash field is omitted, then the hash algorithm SHALL be SHA1. See paragraph 2.1.1.2.5. Turner, et al Expires January 11, 2009 [Page 8] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 SpecifiedCurve is extensible. Extending SpecifiedCurve with new fields or defining a new version number MUST be coordinated with the ANSI X9.62 WG. 2.1.1.2.1. Specified Curve Version The version field in SpecifiedCurve is of SpecifiedCurveVersion type. SpecifiedCurveVersion uses the following ASN.1: SpecifiedCurveVersion ::= INTEGER { ecpVer1(1), ecpVer2(2), ecpVer3(3) } SpecfifiedCurveVersion is ecpVer1, ecpVer2, or ecpVer3. If version is ecpVer1, then the elliptic curve may or may not be verifiably pseudorandom according to whether curve.seed (see paragraph 2.1.1.2.3) is present, and the base point G (see paragraph 2.1.1.2.4) is not generated verifiably pseudorandom. If version is ecpVer2, then the curve and the base point G shall be generated verifiably pseudorandom, and curve.seed SHALL be present. If version is ecpVer3, then the curve is not generated verifiably pseudorandom but the base point G SHALL be generated verifiably pseudorandom from curve.seed, which SHALL be present. Implementations of this document MUST support ecpVer1. 2.1.1.2.2. Field Identifiers The fieldID field in SpecifiedCurve is of FieldID type. Finite fields are represented by values of the parameterized type FieldID, constrained to the values of the objects defined in the information object set FieldTypes. The type FIELD-ID is defined by the following: FIELD-ID ::= TYPE-IDENTIFIER The FieldID parameterized type is defined as follows: FieldID { FIELD-ID:IOSet } ::= SEQUENCE { fieldType FIELD-ID.&id({IOSet}), parameters FIELD-ID.&Type({IOSet}{@fieldType}) } Turner, et al Expires January 11, 2009 [Page 9] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Field types are given in the following information object set: FieldTypes FIELD-ID ::= { { Prime-p IDENTIFIED BY prime-field } | { Characteristic-two IDENTIFIED BY characteristic-two-field }, ... -- Extensible } Two FieldTypes are defined herein: prime-p (see paragraph 2.1.1.2.2.1) and characteristic-two (see paragraph 2.1.1.2.2.2). Implementations claiming conformance to this specification MUST support the prime-p field type and MAY support the characteristic-two field type. FieldTypes is extensible and other documents can specify additional values for FieldTypes. This definition has been made extensible to leave the formal description of the single remaining case, GF(p**n) with p>2 and m>1, for future standardization coordinated with other relevant standards defining organizations. 2.1.1.2.2.1. Prime-p A prime finite field is specified in FieldID.fieldType by the following object identifier: prime-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 1 } The prime finite field parameters specified in FIELD-ID parameters has the following ASN.1 structure: Prime-p ::= INTEGER Prime-p is an integer which is the size of the field. 2.1.1.2.2.2. Characteristic-two A characteristic-two finite field is specified in FieldID.fieldType by the following object identifier: characteristic-two-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 2 } Turner, et al Expires January 11, 2009 [Page 10] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 The characteristic-two finite field parameters specified in FieldID.parameters have the following ASN.1 structure: Characteristic-two ::= SEQUENCE { m INTEGER, -- Field size 2^m basis CHARACTERISTIC-TWO.&id({BasisTypes}), parameters CHARACTERISTIC-TWO.&Type({BasisTypes}{@basis}) } The fields in Characteristic-two have the following meanings: m is the dimension of the field (over GF(2)). basis is the type of basis used to express elements of the field. parameters represent the polynomial used to generate the field. The parameters vary based on the basis. The type CHARACTERISTIC-TWO is defined by the following: CHARACTERISTIC-TWO ::= TYPE-IDENTIFIER The characteristic-two field basis types are given in the following information object set: BasisTypes CHARACTERISTIC-TWO ::= { { NULL IDENTIFIED BY gnBasis } | { Trinomial IDENTIFIED BY tpBasis } | { Pentanomial IDENTIFIED BY ppBasis }, ... -- Extensible } Three basis types are defined herein: normal bases, trinomial bases, and pentanomial bases. Implementation claiming conformance to this document MUST support normal basis and MAY support trimonial and pentanomial bases. BasisTypes is extensible and other documents can specify additional values for BasisTypes. Normal bases are specified in the basis field by the object identifier: gnBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 1 } A normal base has NULL parameters. Turner, et al Expires January 11, 2009 [Page 11] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 A trinomial base specifies the degree of the middle term in the defining trinomial. A trinomial base is identified in the basis field by the object identifier: tpBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 2 } A trinomial base has the following parameters: Trinomial ::= INTEGER A pentanomial base specifies the degrees of the three middle terms in the defining pentanomial. A pentanomial base is identified in the basis field by the object identifier: ppBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 3 } A pentanomial base has the following parameters: Pentanomial ::= SEQUENCE { k1 INTEGER, -- 0 < k1 k2 INTEGER, -- k1 < k2 k3 INTEGER -- k2 < k3 < m } 2.1.1.2.3. Curve The curve field in SpecifiedCurve is of Curve type. Curve uses the following ASN.1 structure: Curve ::= SEQUENCE { a FieldElement, b FieldElement, seed BIT STRING OPTIONAL -- seed MUST be present if version is either -- ecpVer2 or ecpVer3, and it MAY be present for ecpVer1 } FieldElement ::= OCTET STRING The fields in Curve have the following meanings: a and b are the coefficients a and b, respectively, of the elliptic curve E. Each coefficient, a and b, is represented as a Turner, et al Expires January 11, 2009 [Page 12] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 value of type FieldElement. Conversion routines for field element to octet string are found in [SEC1]. seed is an optional parameter that is used to derive the coefficients of a randomly generated elliptic curve. seed MUST be present if version is either ecpVer2 or ecpVer3, and it MAY be present for ecpVer1. The curve generation routine is found in [X9.62]. 2.1.1.2.4. Base The base field in SpecifiedCurve is of ECPoint type. ECPoint uses the following ASN.1 syntax: ECPoint ::= OCTET STRING The contents of ECPoint is the octet string representation of an elliptic curve point. Conversion routines for point to octet string are found in [SEC1]. Note that these octet strings MAY represent an elliptic curve point in compressed or uncompressed form. Implementations that support elliptic curve cryptography according to this document MUST support the uncompressed form and MAY support the compressed form. The routine for generating the random base when SpecifiedECDomain is either ecdpVer2 or ecdpVer3 is found in Appendix B. 2.1.1.2.5. Hash The hash field in SpecifiedCurve is of HashAlgorithm type. HashAlgorithm uses the following ASN.1 syntax: HashAlgorithm ::= AlgorithmIdentifier {{CurveHashFunctions}} CurveHashAlgorithm is restricted to the CurveHashFunctions parameterized type, which uses the following ASN.1 structure: CurveHashFunctions ALGORITHM ::= { ow-sha1 | ow-sha224 | ow-sha256 | ow-sha384 | ow-sha512, ... -- Extensible } Turner, et al Expires January 11, 2009 [Page 13] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 SHA1 [SHS] is defined as follows: ow-sha1 ALGORITHM ::= { OID id-sha1 PARMS NULL } It has the following object identifier: id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } SHA224 [SHS] is defined as follows: ow-sha224 ALGORITHM ::= { OID id-sha224 PARMS NULL } It has the following object identifier: id-sha224 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 4 } SHA256 [SHS] is defined as follows: ow-sha256 ALGORITHM ::= { OID id-sha256 PARMS NULL } It has the following object identifier: id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1 } SHA384 [SHS] is defined as follows: ow-sha384 ALGORITHM ::= { OID id-sha384 PARMS NULL } It has the following object identifier: id-sha384 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 2 } Turner, et al Expires January 11, 2009 [Page 14] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 SHA512 [SHS] is defined as follows: ow-sha512 ALGORITHM ::= { OID id-sha512 PARMS NULL } It has the following object identifier: id-sha512 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 3 } An implementation of this document SHOULD accept values of the parameterized type HashAlgorithm that have no parameters (also called absent) and values that have NULL parameters. These values SHALL be treated equally. (Of course, future extensions to the type parameter CurveHashFunctions might include information objects whose parameters field is more meaningful.) An implementation of this document SHOULD omit (leave absent) the parameters. 2.1.2. Restricted Algorithm Identifiers and Parameters Algorithms used with elliptic curve cryptography fall in to different categories: signature and key agreement algorithms. ECDSA uses the pk-ec described in 2.1.1. Two sets of key agreement algorithms are identified herein: the Elliptic Curve Diffie-Hellman (ECDH) key agreement scheme and the Elliptic Curve Menezes-Qu-Vanstone (ECMQV) key agreement scheme. All algorithms are identified by an OID and have PARMS. The OID varies based on the algorithm but the PARMS are always ECParameters and they MUST always be present (see paragraph 2.1.1). The ECDH is defined as follows: pk-ecDH ALGORITHM ::= { OID id-ecDH PARMS ECParameters } The algorithm identifier is: id-ecDH OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecdh(12) } The ECMQV is defined as follows: pk-ecMQV ALGORITHM ::= { OID id-ecMQV PARMS ECParameters } Turner, et al Expires January 11, 2009 [Page 15] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 The algorithm identifier is: id-ecMQV OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecmqv(13) } 2.2. Subject Public Key The subjectPublicKey from SubjectPublicKeyInfo is the ECC public key. Implementations of elliptic curve cryptography according to this document MUST support the uncompressed form and MAY support the compressed form of the ECC public key. As specified in [SEC1]: The elliptic curve public key (a value of type ECPoint which is an OCTET STRING) is mapped to a subjectPublicKey (a value of type BIT STRING) as follows: the most significant bit of the OCTET STRING value becomes the most significant bit of the BIT STRING value, and so on; the least significant bit of the OCTET STRING becomes the least significant bit of the BIT STRING. The first octet of the OCTET STRING indicates whether the key is compressed or uncompressed. The uncompressed form is indicated by 0x04 and the compressed form is indicated by either 0x02 or 0x03 (see 2.3.3 in [SEC1]). 3. Key Usage Bits If the keyUsage extension is present in a CA certificate that indicates id-ecPublicKey in subjectPublicKeyInfo, any combination of the following values MAY be present: digitalSignature; nonRepudiation; keyAgreement; keyCertSign; and cRLSign. If the CA certificate keyUsage extension asserts keyAgreement then it MAY assert either encipherOnly or decipherOnly. However, this specification RECOMMENDS that if keyCertSign or cRLSign is present, keyAgreement, encipherOnly, and decipherOnly SHOULD NOT be present. Turner, et al Expires January 11, 2009 [Page 16] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 If the keyUsage extension is present in an EE certificate that indicates id-ecPublicKey in subjectPublicKeyInfo, any combination of the following values MAY be present: digitalSignature; nonRepudiation; and keyAgreement. If the EE certificate keyUsage extension asserts keyAgreement then it MAY assert either encipherOnly or decipherOnly. If the keyUsage extension is present in a certificate that indicates ecDH or ecMQV in subjectPublicKeyInfo, keyAgreement MUST be present and digitalSignature, nonRepudiation, keyTransport, keyCertSign, and cRLSign MUST NOT be present. If this certificate keyUsage extension asserts keyAgreement then it MAY assert either encipherOnly or decipherOnly. 4. Security Considerations The security considerations in [RFC3279] apply. When implementing ECC in X.509 Certificates, there are three algorithm related choices that need to be made: 1) What is the public key size? 2) What is the hash algorithm? 3) What is the curve? Consideration must be given to the strength of the security provided by each of these choices. Security is measured in bits, where a strong symmetric cipher with a key of X bits is said to provide X bits of security. It is recommended that the bits of security provided by each choice are roughly equivalent. The following table provides comparable minimum bits of security [SP800-57] for the ECDSA key sizes and message digest algorithms. It also lists curves (see paragraph 2.1.1.1) for the key sizes. Using a larger hash value and then truncating it, consumes more processing power than is necessary. This is more important on constrained devices. Since the signer does not know the environment that the recipient will use to validate the signature, it is better to use a hash function that provides the desired have value output size, and no more. Turner, et al Expires January 11, 2009 [Page 17] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Minimum | ECDSA | Message | Curves Bits of | Key Size | Digest | Security | | Algorithms | ---------+----------+------------+----------- 80 | 160-223 | SHA1 | sect163k1 | | SHA224 | secp163r2 | | SHA256 | secp192r1 | | SHA384 | | | SHA512 | ---------+----------+------------+----------- 112 | 224-255 | SHA224 | secp224r1 | | SHA256 | sect233k1 | | SHA384 | sect233r1 | | SHA512 | ---------+----------+------------+----------- 128 | 256-383 | SHA256 | secp256r1 | | SHA384 | sect283k1 | | SHA512 | sect283r1 ---------+----------+------------+----------- 192 | 384-511 | SHA384 | secp384r1 | | SHA512 | sect409k1 | | | sect409r1 ---------+----------+------------+----------- 256 | 512+ | SHA512 | secp521r1 | | | sect571k1 | | | sect571r1 ---------+----------+------------+----------- To promote interoperability, the following choices are RECOMMENDED: Minimum | ECDSA | Message | Curves Bits of | Key Size | Digest | Security | | Algorithms | ---------+----------+------------+----------- 80 | 192 | SHA256 | secp192r1 ---------+----------+------------+----------- 112 | 224 | SHA256 | secp224r1 ---------+----------+------------+----------- 128 | 256 | SHA256 | secp256r1 ---------+----------+------------+----------- 192 | 384 | SHA384 | secp384r1 ---------+----------+------------+----------- 256 | 512 | SHA512 | secp521r1 ---------+----------+------------+----------- Turner, et al Expires January 11, 2009 [Page 18] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 5. IANA Considerations This document makes extensive use of object identifiers to register public key types, elliptic curves, field types, and hash algorithms. Most are registered in the ANSI X9.62 arc with exception of the hash algorithms, which are in NIST's arc, and many of the curves, which are in Certicom Inc. arc (these curves have adopted by ANSI and NIST). Additionally, object identifiers are used to identify the ASN.1 modules found in Appendix A. These are defined in an arc delegated by IANA to the PKIX Working Group. No further action by IANA is necessary for this document or any anticipated updates. 6. Acknowledgements The authors wish to thank Alfred Hines and Jim Schaad for their valued input. 7. References 7.1. Normative References [DSS] Federal Information Processing Standards Publication (FIPS PUB) 186-2, Digital Signature Standard, January 2000. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5280] D., Copper, et al., "Internet X.509 Public Key Infrastructure Certificate and Certification Revocation List (CRL) Profile", RFC 5280, May 2008. [SHS] National Institute of Standards and Technology (NIST), FIPS Publication 180-2: Secure Hash Standard, August 2002. [SEC1] Standards for Efficient Cryptography, "SEC 1: Elliptic Curve Cryptography", Version 1.0, September 2000. [X9.62] American National Standards Institute (ANSI), ANS X9.62- 2005: The Elliptic Curve Digital Signature Algorithm (ECDSA), 2005. [X.208] ITU-T Recommendation X.208 (1988) | ISO/IEC 8824-1:1988. Specification of Abstract Syntax Notation One (ASN.1). Turner, et al Expires January 11, 2009 [Page 19] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 [X.680] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002. Information Technology - Abstract Syntax Notation One. [X.681] ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-2:2002. Information Technology - Abstract Syntax Notation One: Information Object Specification. [X.682] ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-3:2002. Information Technology - Abstract Syntax Notation One: Constraint Specification. [X.683] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-4:2002. Information Technology - Abstract Syntax Notation One: Parameterization of ASN.1 Specifications. 7.2. Informative References [RFC3279] Polk, W., Housley, R. and L. Bassham, "Algorithm Identifiers for the Internet X.509 Public Key Infrastructure", RFC 3279, April 2002. [SP800-57] National Institute of Standards and Technology (NIST), Special Publication 800-57: Recommendation for Key Management, August 2005. Turner, et al Expires January 11, 2009 [Page 20] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Appendix A. ASN.1 Modules Appendix A.1 provides the normative ASN.1 definitions for the structures described in this specification using ASN.1 as defined in [X.208]. Appendix A.2 provides an informative ASN.1 definitions for the structures described in this specification using ASN.1 as defined in [X.680], [X.681], [X.682], and [X.683]. This appendix contains the same information as Appendix A.1 in a more recent (and precise) ASN.1 notation, however Appendix A.1 takes precedence in case of conflict. These modules include more than the ASN.1 updates described in the text of this document. They also include additional ASN.1 from [RFC3279] because this document updates the entire ASN.1 module. Appendix A.1. 1988 ASN.1 Module PKIXAlgs-1988 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) TBD } DEFINITIONS EXPLICIT TAGS ::= BEGIN -- EXPORTS ALL IMPORTS AlgorithmIdentifier FROM PKIX1Explicit88 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) mod(0) pkix1-explicit(18) } ; -- -- Public Key (pk) Algorithms -- -- RSA PK Algorithm, Parameters, and Keys rsaEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 1 } Turner, et al Expires January 11, 2009 [Page 21] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 RSAPublicKey ::= SEQUENCE { modulus INTEGER, -- n publicExponent INTEGER -- e } -- DSA PK Algorithm and Parameters id-dsa OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) x9-57(10040) x9algorithm(4) 1 } DSAPublicKey ::= INTEGER -- public key, y DSS-Parms ::= SEQUENCE { p INTEGER, q INTEGER, g INTEGER } -- Diffie-Hellman PK Algorithm, Keys, and Parameters dhpublicnumber OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-x942(10046) number-type(2) 1 } DHPublicKey ::= INTEGER -- public key, y = g^x mod p DomainParameters ::= SEQUENCE { p INTEGER, -- odd prime, p=jq +1 g INTEGER, -- generator, g q INTEGER, -- factor of p-1 j INTEGER OPTIONAL, -- subgroup factor, j>= 2 validationParms ValidationParms OPTIONAL } ValidationParms ::= SEQUENCE { seed BIT STRING, pgenCounter INTEGER } -- KEA PK Algorithm and Parameters id-keyExchangeAlgorithm OBJECT IDENTIFIER ::= { 2 16 840 1 101 2 1 1 22 } KEA-Parms-Id ::= OCTET STRING -- Sec 2.1.1 Unrestricted Algorithms and Parameters (including ECDSA) id-ecPublicKey OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 } Turner, et al Expires January 11, 2009 [Page 22] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- Sec 2.1.2 Restricted Algorithms and Parameters id-ecDH OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecdh(12) } -- Sec 2.1.2 Restricted Algorithms and Parameters id-ecMQV OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecmqv(13) } -- Parameters for both Restricted and Unrestricted ECParameters ::= CHOICE { namedCurve OBJECT IDENTIFIER, specifiedCurve SpecifiedCurve, implicitCurve NULL } -- Sec 2.1.1.1 Named Curves -- Note in [X9.62] the curves are referred to as 'ansiX9' as -- opposed to 'sec'. For example secp192r1 is the same curve as -- ansix9p192r1. -- Note that in [RFC3279] the secp192r1 curve was referred to as -- prime192v1 and the secp256v1 curve was referred to as secp256r1. -- Note that [DSS] refers to secp192r1 as P-192, secp224r1 as P-224, -- secp384r1 as P-384, secp521r1 as P-521. secp192r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 1 } sect163k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 1 } sect163r2 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 15 } secp224r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 33 } sect233k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 26 } Turner, et al Expires January 11, 2009 [Page 23] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 sect233r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 27 } secp256r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 7 } sect283k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 16 } sect283r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 17 } secp384r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 34 } sect409k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 36 } sect409r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 37 } secp521r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 35 } sect571k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 38 } sect571r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 39 } -- Sec 2.1.1.2 Specified Curve SpecifiedCurve ::= SEQUENCE { version SpecifiedCurveVersion, fieldID FieldID, curve Curve, -- Curve E base ECPoint, -- Base point G order INTEGER, -- Order n of the base point cofactor INTEGER OPTIONAL, -- The integer h = #E(Fq)/n hash HashAlgorithm OPTIONAL } Turner, et al Expires January 11, 2009 [Page 24] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 SpecifiedCurveVersion ::= INTEGER { ecpVer1(1), ecpVer2(2), ecpVer3(3) } FieldID ::= SEQUENCE { fieldType OBJECT IDENTIFIER, parameters ANY DEFINED BY fieldType } -- where fieldType is prime-field, the parameters are of type Prime-p prime-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 1 } Prime-p ::= INTEGER -- where fieldType is characteristic-two-field, the parameters are -- of type Characteristic-two characteristic-two-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 2 } Characteristic-two ::= SEQUENCE { m INTEGER, -- Field size 2^m basis OBJECT IDENTIFIER, parameters ANY DEFINED BY basis } -- The object identifiers gnBasis, tpBasis and ppBasis name -- three kinds of basis for characteristic-two finite fields -- normal basis is identified by OID gnBasis and indicates -- parameters are NULL gnBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 1 } -- trinomial basis is identified by OID tpBasis and indicates -- parameters of type Pentanomial tpBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 2 } Turner, et al Expires January 11, 2009 [Page 25] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Trinomial ::= INTEGER -- Trinomial basis representation of F2^m -- Integer k for reduction polynomial x**m + x**k + 1 -- pentanomial basis is identified by OID ppBasis and indicates -- parameters of type Pentanomial ppBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 3 } -- Pentanomial basis representation of F2^m -- reduction polynomial integers k1, k2, k3 -- f(x) = x**m + x**k3 + x**k2 + x**k1 + 1 Pentanomial ::= SEQUENCE { k1 INTEGER, -- 0 < k1 k2 INTEGER, -- k1 < k2 k3 INTEGER -- k2 < k3 < m } Curve ::= SEQUENCE { a FieldElement, -- Elliptic curve coefficient a b FieldElement, -- Elliptic curve coefficient b seed BIT STRING OPTIONAL -- seed MUST be present if version is either -- ecpVer2 or ecpVer3, and it MAY be present for ecpVer1 } FieldElement ::= OCTET STRING ECPoint ::= OCTET STRING HashAlgorithm ::= AlgorithmIdentifier -- -- Signature Algorithms (sa) -- -- RSA with MD-2 md2WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 2 } Turner, et al Expires January 11, 2009 [Page 26] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- RSA with MD-5 md5WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 4 } -- RSA with SHA-1 sha1WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 5 } -- DSA with SHA-1 dsa-with-sha1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) x9-57(10040) x9algorithm(4) 3 } -- ECDSA with SHA-1 ecdsa-with-SHA1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) signatures(4) 1 } -- -- Signature Values -- -- DSA DSA-Sig-Value ::= SEQUENCE { r INTEGER, s INTEGER } -- ECDSA ECDSA-Sig-Value ::= SEQUENCE { r INTEGER, s INTEGER } -- -- One-way (ow) Hash Algorithms -- -- MD-2 id-md2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) digestAlgorithm(2) 2 } Turner, et al Expires January 11, 2009 [Page 27] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- MD-5 id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549)digestAlgorithm(2) 5 } -- SHA-1 id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } -- SHA-224 id-sha224 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 4 } -- SHA-256 id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1 } -- SHA-384 id-sha384 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 2 } -- SHA-512 id-sha512 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 3 } END Turner, et al Expires January 11, 2009 [Page 28] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Appendix A.2. 2004 ASN.1 Module PKIXAlgs-2008 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) TBD } DEFINITIONS EXPLICIT TAGS ::= BEGIN -- EXPORTS ALL -- IMPORTS NONE ALGORITHM ::= CLASS { &id OBJECT IDENTIFIER UNIQUE, &Type OPTIONAL } WITH SYNTAX { OID &id [PARMS &Type] } AlgorithmIdentifier {ALGORITHM:IOSet} ::= SEQUENCE { algorithm ALGORITHM.&id({IOSet}), parameters ALGORITHM.&Type({IOSet}{@algorithm}) OPTIONAL } -- -- Public Key (pk) Algorithms -- PKAlgorithms ALGORITHM ::= { pk-rsa | pk-dsa | pk-dh | pk-kea | pk-ec | pk-ecDH | pk-ecMQV, ... -- Extensible } -- RSA PK Algorithm, Parameters, and Keys pk-rsa ALGORITHM ::= { OID rsaEncryption PARMS NULL } rsaEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 1 } Turner, et al Expires January 11, 2009 [Page 29] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 RSAPublicKey ::= SEQUENCE { modulus INTEGER, -- n publicExponent INTEGER -- e } -- DSA PK Algorithm, Parameters, and Keys pk-dsa ALGORITHM ::= { OID id-dsa PARMS DSS-Parms } id-dsa OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) x9-57(10040) x9algorithm(4) 1 } DSS-Parms ::= SEQUENCE { p INTEGER, q INTEGER, g INTEGER } DSAPublicKey ::= INTEGER -- public key, y -- Diffie-Hellman PK Algorithm, Parameters, and Keys pk-dh ALGORITHM ::= { OID dhpublicnumber PARMS DomainParameters } dhpublicnumber OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-x942(10046) number-type(2) 1 } DomainParameters ::= SEQUENCE { p INTEGER, -- odd prime, p=jq +1 g INTEGER, -- generator, g q INTEGER, -- factor of p-1 j INTEGER OPTIONAL, -- subgroup factor, j>= 2 validationParms ValidationParms OPTIONAL } ValidationParms ::= SEQUENCE { seed BIT STRING, pgenCounter INTEGER } DHPublicKey ::= INTEGER -- public key, y = g^x mod p -- KEA PK Algorithm and Parameters pk-kea ALGORITHM ::= { OID id-keyExchangeAlgorithm PARMS KEA-Parms-Id } Turner, et al Expires January 11, 2009 [Page 30] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 id-keyExchangeAlgorithm OBJECT IDENTIFIER ::= { 2 16 840 1 101 2 1 1 22 } KEA-Parms-Id ::= OCTET STRING -- Sec 2.1.1 Unrestricted Algorithms and Parameters (including ECDSA) pk-ec ALGORITHM ::= { OID id-ecPublicKey PARMS ECParameters } id-ecPublicKey OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 } -- Sec 2.1.2 Restricted Algorithms and Parameters pk-ecDH ALGORITHM ::= { OID id-ecDH PARMS ECParameters } id-ecDH OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecdh(12) } -- Sec 2.1.2 Restricted Algorithms and Parameters pk-ecMQV ALGORITHM ::= { OID id-ecMQV PARMS ECParameters } id-ecMQV OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) schemes(1) ecmqv(13) } -- Parameters for both Restricted and Unrestricted ECParameters ::= CHOICE { namedCurve CURVE.&id({NamedCurve}), specifiedCurve SpecifiedCurve, implicitCurve NULL } -- Sec 2.1.1.1 Named Curve CURVE ::= CLASS { &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { ID &id } Turner, et al Expires January 11, 2009 [Page 31] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 NamedCurve CURVE ::= { { ID secp192r1 } | { ID sect163k1 } | { ID sect163r2 } | { ID secp224r1 } | { ID sect233k1 } | { ID sect233r1 } | { ID secp256r1 } | { ID sect283k1 } | { ID sect283r1 } | { ID secp384r1 } | { ID sect409k1 } | { ID sect409r1 } | { ID secp521r1 } | { ID sect571k1 } | { ID sect571r1 }, ... -- Extensible } -- Note in [X9.62] the curves are referred to as 'ansiX9' as -- opposed to 'sec'. For example secp192r1 is the same curve as -- ansix9p192r1. -- Note that in [RFC3279] the secp192r1 curve was referred to as -- prime192v1 and the secp256v1 curve was referred to as secp256r1. -- Note that [DSS] refers to secp192r1 as P-192, secp224r1 as P-224, -- secp384r1 as P-384, secp521r1 as P-521. secp192r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 1 } sect163k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 1 } sect163r2 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 15 } secp224r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 33 } sect233k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 26 } sect233r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 27 } secp256r1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3) prime(1) 7 } sect283k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 16 } sect283r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 17 } Turner, et al Expires January 11, 2009 [Page 32] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 secp384r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 34 } sect409k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 36 } sect409r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 37 } secp521r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 35 } sect571k1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 38 } sect571r1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) certicom(132) curve(0) 39 } -- Sec 2.1.1.2 Specified Curve SpecifiedCurve ::= SEQUENCE { version SpecifiedCurveVersion ( ecpVer1 | ecpVer2 | ecpVer3, ... ), fieldID FieldID {{FieldTypes}}, curve Curve, -- Curve E base ECPoint, -- Base point G order INTEGER, -- Order n of the base point cofactor INTEGER OPTIONAL, -- The integer h = #E(Fq)/n hash HashAlgorithm OPTIONAL, ... -- Extensible } SpecifiedCurveVersion ::= INTEGER { ecpVer1(1), ecpVer2(2), ecpVer3(3) } FIELD-ID ::= TYPE-IDENTIFIER FieldID { FIELD-ID:IOSet } ::= SEQUENCE { fieldType FIELD-ID.&id({IOSet}), parameters FIELD-ID.&Type({IOSet}{@fieldType}) } Turner, et al Expires January 11, 2009 [Page 33] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 FieldTypes FIELD-ID ::= { { Prime-p IDENTIFIED BY prime-field } | { Characteristic-two IDENTIFIED BY characteristic-two-field }, ... -- Extensible } -- where fieldType is prime-field, the parameters are of type Prime-p prime-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 1 } Prime-p ::= INTEGER -- where fieldType is characteristic-two-field, the parameters are -- of type Characteristic-two characteristic-two-field OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(1) 2 } Characteristic-two ::= SEQUENCE { m INTEGER, -- Field size 2^m basis CHARACTERISTIC-TWO.&id({BasisTypes}), parameters CHARACTERISTIC-TWO.&Type({BasisTypes}{@basis}) } CHARACTERISTIC-TWO ::= TYPE-IDENTIFIER -- The object identifiers gnBasis, tpBasis and ppBasis name -- three kinds of basis for characteristic-two finite fields BasisTypes CHARACTERISTIC-TWO ::= { { NULL IDENTIFIED BY gnBasis } | { Trinomial IDENTIFIED BY tpBasis } | { Pentanomial IDENTIFIED BY ppBasis }, ... -- Extensible } -- normal basis is identified by OID gnBasis and indicates -- parameters are NULL gnBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 1 } Turner, et al Expires January 11, 2009 [Page 34] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- trinomial basis is identified by OID tpBasis and indicates -- parameters of type Trinomial tpBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 2 } Trinomial ::= INTEGER -- Trinomial basis representation of F2^m -- Integer k for reduction polynomial x**m + x**k + 1 -- pentanomial basis is identified by OID ppBasis and indicates -- parameters of type Pentanomial ppBasis OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) fieldType(2) characteristic-two-basis(2) basisType(3) 3 } -- Pentanomial basis representation of F2^m -- reduction polynomial integers k1, k2, k3 -- f(x) = x**m + x**k3 + x**k2 + x**k1 + 1 Pentanomial ::= SEQUENCE { k1 INTEGER, -- 0 > k1 k2 INTEGER, -- k1 < k2 k3 INTEGER -- k2 < k3 < m } Curve ::= SEQUENCE { a FieldElement, b FieldElement, seed BIT STRING OPTIONAL -- seed MUST be present if version is either -- ecpVer2 or ecpVer3, and it MAY be present for ecpVer1 } FieldElement ::= OCTET STRING ECPoint ::= OCTET STRING HashAlgorithm ::= AlgorithmIdentifier {{CurveHashFunctions}} Turner, et al Expires January 11, 2009 [Page 35] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 CurveHashFunctions ALGORITHM ::= { ow-sha1 | ow-sha224 | ow-sha256 | ow-sha384 | ow-sha512, ... -- Extensible } -- -- Signature Algorithms (sa) -- SignatureAlgorithms ALGORITHM ::= { sa-rsaWithMD2 | sa-rsaWithMD5 | sa-rsaWithSHA1 | sa-dsawithSHA1 | sa-ecdsaWithSHA1, ... -- Extensible } -- RSA with MD-2 sa-rsaWithMD2 ALGORITHM ::= { OID md2WithRSAEncryption PARMS NULL } md2WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 2 } -- RSA with MD-5 sa-rsaWithMD5 ALGORITHM ::= { OID md5WithRSAEncryption PARMS NULL } md5WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 4 } -- RSA with SHA-1 sa-rsaWithSHA1 ALGORITHM ::= { OID sha1WithRSAEncryption PARMS NULL } sha1WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 5 } Turner, et al Expires January 11, 2009 [Page 36] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- DSA with SHA-1 sa-dsaWithSHA1 ALGORITHM ::= { OID dsa-with-sha1 PARMS NULL } dsa-with-sha1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) x9-57(10040) x9algorithm(4) 3 } -- ECDSA with SHA-1 sa-ecdsaWithSHA1 ALGORITHM ::= { OID ecdsa-with-sha1 PARMS NULL } ecdsa-with-SHA1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) ansi-X9-62(10045) signatures(4) 1 } -- -- Signature Values -- -- DSA DSA-Sig-Value ::= SEQUENCE { r INTEGER, s INTEGER } -- ECDSA ECDSA-Sig-Value ::= SEQUENCE { r INTEGER, s INTEGER } Turner, et al Expires January 11, 2009 [Page 37] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 -- -- One-way (ow) Hash Algorithms -- HashAlgorithms ALGORITHM ::= { ow-md2 | ow-md5 | ow-sha1 | ow-sha224 | ow-sha256 | ow-sha384 | ow-sha512, ... -- Extensible } -- MD-2 ow-md2 ALGORITHM ::= { OID id-md2 PARMS NULL } id-md2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) digestAlgorithm(2) 2 } -- MD-5 ow-md5 ALGORITHM ::= { OID id-md5 PARMS NULL } id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549)digestAlgorithm(2) 5 } -- SHA-1 ow-sha1 ALGORITHM ::= { OID id-sha1 PARMS NULL } id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } -- SHA-224 ow-sha224 ALGORITHM ::= { OID id-sha224 PARMS NULL } Turner, et al Expires January 11, 2009 [Page 38] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 id-sha224 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 4 } -- SHA-256 ow-sha256 ALGORITHM ::= { OID id-sha256 PARMS NULL } id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1 } -- SHA-384 ow-sha384 ALGORITHM ::= { OID id-sha384 PARMS NULL } id-sha384 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 2 } -- SHA-512 ow-sha512 ALGORITHM ::= { OID id-sha512 PARMS NULL } id-sha512 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistalgorithm(4) hashalgs(2) 3 } END Turner, et al Expires January 11, 2009 [Page 39] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Appendix B. Random Base Generation Routine This Appendix is normative. Appendix B.1. Generation of Random Candidate Point Inputs: Bit string SEED, integer counter basecount, selected hash function with output length hashlen bits, field size q, cofactor h. (See [X9.62] for descriptions of these quantities.) Actions: The following or its equivalent: a) Set element = 1. b) Convert basecount and element to octet strings BaseCount and Element of minimal length, respectively. c) Compute H = Hash ("Base point" || BaseCount || Element || SEED). d) Convert H to an integer e, using A.5 of [X9.62]. e) Let t = e mod 2q, so that t is an integer in the interval [0, 2q - 1]. f) Let x = t mod q and z = Floor[t / q]. g) Convert x to field element in Fq using A.5 of [X9.62]. h) Recover the field element y from (x, z) using the appropriate method from A.3.1.3 of [X9.62]. i) If the result is an error, then increment element and go back to Step b). Output: A random candidate point (x, y). Turner, et al Expires January 11, 2009 [Page 40] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Appendix B.2. Generation of Random Base Input: Elliptic curve E = (Fq, a, b), cofactor h, prime n, and bit string SEED. (See [X9.62] for descriptions of these quantities.) Actions: The following or its equivalent: a) Set basecount = 1. b) Generate a random candidate point R = (x, y) using Annex B.1 with the current value of basecount. c) Let G = hR. d) If g = 0 or nG not = 0, then increment basecount and go back to Step b), unless base > 10h^2, in which case, output "Failure". Output: A random base G, or "Failure". Turner, et al Expires January 11, 2009 [Page 41] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Authors' Addresses Sean Turner IECA, Inc. 3057 Nutley Street, Suite 106 Fairfax, VA 22031 USA EMail: turners@ieca.com Kelvin Yiu Microsoft One Microsoft Way Redmond, WA 98052-6399 USA Email: kelviny@microsoft.com Daniel R. L. Brown Certicom Corp 5520 Explorer Drive #400 Mississauga, ON L4W 5L1 CANADA EMail: dbrown@certicom.com Russ Housley Vigil Security, LLC 918 Spring Knoll Drive Herndon, VA 20170 USA EMail: housley@vigilsec.com Tim Polk NIST Building 820, Room 426 Gaithersburg, MD 20899 USA EMail: wpolk@nist.gov Turner, et al Expires January 11, 2009 [Page 42] Internet-Draft ECC SubjectPublicKeyInfo Format July 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Turner, et al Expires January 11, 2009 [Page 43]