One document matched: draft-ietf-pkix-ecc-subpubkeyinfo-01.txt

Differences from draft-ietf-pkix-ecc-subpubkeyinfo-00.txt


PKIX Working Group                                    Sean Turner, IECA 
Internet Draft                                   Daniel Brown, Certicom 
Intended Status: Standard Track                   Kelvin Yiu, Microsoft 
Expires: July 2, 2008                      Russ Housley, Vigil Security 
                                                         Tim Polk, NIST 
                                                       22 January, 2008 
                                      
        Elliptic Curve Cryptography Subject Public Key Information 
                 draft-ietf-pkix-ecc-subpubkeyinfo-01.txt 


Status of this Memo 

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   This Internet-Draft will expire on July 22, 2008. 

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 [RFC3279]. 



 
 
 
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Table of Contents 

   1. Introduction......................................... 2 
      1.1. Terminology..................................... 3 
   2. Subject Public Key Information Fields.................... 3 
      2.1. Elliptic Curve Public Key Algorithm Identifier......... 4 
         2.1.1. Unrestricted Identifiers and Parameters.......... 5 
            2.1.1.1. Named Curve............................. 5 
            2.1.1.2. Specified Curve.......................... 7 
               2.1.1.2.1. Specified Curve Version............... 8 
               2.1.1.2.2. Field Identifiers.................... 9 
                  2.1.1.2.2.1. Prime-p........................ 9 
                  2.1.1.2.2.2. Characteristic-two.............. 10 
               2.1.1.2.3. Curve............................. 12 
               2.1.1.2.4. Base.............................. 12 
               2.1.1.2.5. Hash.............................. 12 
         2.1.2. Restricted Algorithm Identifiers and Parameters... 14 
      2.2. Subject Public Key............................... 15 
   3. KeyUsage Bits....................................... 15 
   4. Security Considerations............................... 16 
   5. IANA Considerations.................................. 16 
   6. References......................................... 16 
      6.1. Normative References............................. 16 
      6.2. Informative References........................... 17 
   Appendix A. ASN.1 Module................................ 17 
    
1. Introduction 

   This document specifies the format of the subjectPublicKeyInfo field 
   in X.509 certificates [RFC3280] that use Elliptic Curve Cryptography 
   (ECC).  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 Elliptic Curve Menezes-Qu-Vanstone (ECMQV) family 
      schemes. 

   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. 


 
 
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   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. 

   Specification of all EC parameters is complicated with many options.  
   To promote interoperability, this document indicates which options 
   are required. 

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 subjectPublilcKeyInfo field has the 
   SubjectPublicKeyInfo type, which has the following ASN.1 syntax: 

     SubjectPublicKeyInfo  ::=  SEQUENCE  { 
       algorithm         AlgorithmIdentifier {{ECPKAlgorithms}}, 
       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. 

   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 
 
 
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   are defined in this document: ECPKAlgorithms (see paragraph 2.1) and 
   HashFunctions (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 Public Key Algorithm Identifier 

   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 
   ECPKCAlgorithms parameterized type, which uses the following ASN.1 
   structure: 

     ECPKAlgorithms ALGORITHM ::= { 
       ecPublicKeyType | 
       ecDH | 
       ecMQV  
     } 

   The algorithms defined are as follows: 

      ecPublicKeyType 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 
      ecPublicKeyType MUST be supported.  See paragraph 2.1.1. This 
      value is also used when a key is used with ECDSA. 

      ecDH and ecMQV MAY be supported.  See paragraph 2.1.2. 





 
 
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2.1.1. Unrestricted Identifiers and Parameters 

   The "unrestricted" algorithm is defined as follows: 

    ecPublicKeyType 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: 

     ECParameters ::= CHOICE { 
       namedCurve      CURVE.&id({NamedCurve}), 
       specifiedCuve   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 
      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 ECParamaters 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 } 

 
 
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   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: 

   secp192r1 OBJECT IDENTIFIER ::= { 
     ansi-x9-62 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 ::= { 
     ansi-x9-62 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 } 


 
 
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   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 } 

2.1.1.2. Specified Curve 

   The specified field in ECParameters is the 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 P 
       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 P of 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 P, specified in 
      base. 


 
 
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      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 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 P, specified in 
      the base field, verifiably psuedorandomly.  If the hash field is 
      omitted, then the hash algorithm shall be SHA1.  See paragraph 
      2.1.1.2.5. 

   SpecifiedCurve is extensible and other documents may specify 
   additional fields for this ASN.1 structure. 

2.1.1.2.1. Specified Curve Version 

   The version field in SpecifiedCurve is the SpecifiedCurveVersion 
   type.  SpecifiedCurveVersion uses the following ASN.1 structure: 

     SpecifiedCurveVersion ::= INTEGER { 
       ecpVer1(1), 
       ecpVer2(2), 
       ecpVer3(3), 
       ... -- Extensible 
     } 

   SpecfifiedCurveVersion is ecdpVer1, ecdpVer2, or ecdpVer3.  If 
   version is ecdpVer1, then the elliptic curve may or may not be 
   verifiably psuedorandomly 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 psuedorandomly. If version is 
   ecdpVer2, then the curve and the base point G shall be generated 
   verifiably psuedorandomly, and curve.seed shall be present. If 
   version is ecdpVer3, then the curve is not generated verifiably 
   psuedorandomly but the base point G shall be generated verifiably 
   psuedorandomly from curve.seed, which shall be present. 

   SpecifiedCurveVersion is extensible and other documents can specify 
   additional values for SpecifiedCurveVersion. 

   Implementations of this document MUST support ecpVer1. 




 
 
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2.1.1.2.2. Field Identifiers 

   The fieldID field in SpecifiedCurve is the 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}) 
     } 

   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 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. 

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. 
 
 
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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 } 

   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 size of the field.  

      basis is the type of basis used to express elements of the field. 

      parameters is 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. 


 
 
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   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) 1 } 

   A normal base has NULL parameters. 

   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) 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 pentaomial 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) 3 } 

   A pentanomial base has the following parameters: 

     Pentanomial ::= SEQUENCE { 
       k1 INTEGER, -- k1 > 0 
       k2 INTEGER, -- k2 > k1 
       k3 INTEGER  -- k3 > k2 
     } 











 
 
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2.1.1.2.3. Curve 

   The curve field in SpecifiedCurve is the Curve type.  Curve uses the 
   following ASN.1 structure: 

     Curve ::= SEQUENCE { 
       a     FieldElement, 
       b     FieldElement, 
       seed  BIT STRING OPTIONAL 
       -- Shall be present if used in SpecifiedCurve 
       -- with version of ecdpVer2 or ecdpVer3 
     } 

     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, shall be represented 
      as a value of type FieldElement.  Conversion routines for field 
      element 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 according to this document MUST support the uncompressed 
      form and MAY support the compressed form. 

      seed is an optional parameter that is used to derive the 
      coefficients of a randomly generated elliptic curve.  seed MUST 
      be present if SpecifiedECDomain is either ecdpVer2 or ecdpVer3. 

2.1.1.2.4. Base 

   The base field in SpecifiedCurve is the 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]. 

2.1.1.2.5. Hash 

   The hash field in SpecifiedCurve is the HashAlgorithm type.  
   HashAlgorithm use the following ASN.1 syntax: 

     HashAlgorithm ::= AlgorithmIdentifier {{HashFunctions}} 
 
 
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   HashAlgorithm is restricted to the HashFunctions parameterized type, 
   which uses the following ASN.1 structure: 

     HashFunctions ALGORITHM ::= { 
       sha1   | 
       sha224 | 
       sha256 | 
       sha384 | 
       sha512 | 
       ... -- Extensible 
     } 

   The SHA1 [SHA2] algorithm is defined as follows: 

     sha1 ALGORITHM ::= { 
       OID id-sha1 PARMS NULL } 

   The algorithm identifier is: 

      id-sha1 OBJECT IDENTIFIER ::= { 
        iso(1) identified-organization(3) oiw(14) secsig(3) 
        algorithm(2) 26 } 

   The SHA224 [SHA2] algorithm is defined as follows: 

     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 }  

   The SHA256 [SHA2] algorithm is defined as follows: 

     sha256 ALGORITHM ::= { 
     OID id-sha256 PARMS NULL } 

   The algorithm identifier is: 

     id-sha256 OBJECT IDENTIFIER ::= { 
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) 
       csor(3) nistalgorithm(4) hashalgs(2) 1 } 



 
 
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   The SHA384 [SHA2] algorithm is defined as follows: 

     sha384 ALGORITHM ::= { 
       OID id-sha384 PARMS NULL } 

   The algorithm identifier is: 

     id-sha384 OBJECT IDENTIFIER ::= { 
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) 
       csor(3) nistalgorithm(4) hashalgs(2) 2 } 

   The SHA512 [SHA2] algorithm is defined as follows: 

     sha512 ALGORITHM ::= { 
       OID id-sha512 PARMS NULL }  

   The algorithm identifier is: 

     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 
   HashFunctions might include information objects whose parameters 
   field is more meaningful.) An implementation of this document SHOULD 
   omit (leave absent) the parameters unless the recipient 
   implementation is unable to process absent parameters correctly. 

2.1.2. Restricted Algorithm Identifiers and Parameters 

   Algorithms used with EC fall in to different categories: signature 
   and key agreement algorithms.  ECDSA uses the ecPublicKey described 
   in 2.1.1. Two sets of key agreement algorithms are identified herein: 
   Elliptic Curve Diffie-Hellman (ECDH) key agreement scheme and 
   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 (see 
   paragraph 2.1.1). 

   The ECDH is defined as follows: 

     ecDH ALGORITHM ::= { 
       OID TBD PARMS ECParameters } 

 
 
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   The algorithm identifier is: 

     TBD OBJECT IDENTIFIER ::= { 
       TBD }  

   The ECMQV is defined as follows: 

     ecMQV ALGORITHM ::= { 
       OID TBD PARMS ECParameters }  

   The algorithm identifier is: 

     TBD OBJECT IDENTIFIER ::= { 
       TBD }  

2.2. Subject Public Key 

   The subjectPublicKey from SubjectPublicKeyInfo is the ECC public key.  
   Implementations that support elliptic curve 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 first two bytes of the key indicate whether the key is 
      compressed or uncompressed. 

      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. 

3. KeyUsage 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 

 
 
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   specification RECOMMENDS that if keyCertSign or cRLSign is present, 
   keyAgreement, encipherOnly, and decipherOnly SHOULD NOT be present. 

   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.  However, this 
   specification RECOMMENDS that if cRLSign is present, then 
   keyAgreement, encipherOnly, and decipherOnly SHOULD NOT be present. 

   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. No new security 
   considerations are introduced by this document. 

5. IANA Considerations 

   None.  Please remove this section prior to publication as an RFC. 

6. References 

6.1. Normative References 

   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate 
               Requirement Levels", BCP 14, RFC 2119, March 1997. 

   [RFC3280]   Housley, R., Polk, W., Ford, W., and D. Solo, "Internet 
               X.509 Public Key Infrastructure Certificate and 
               Certification Revocation List (CRL) Profile", RFC 3280, 
               April 2002. 

   [SHA2]      National Institute of Standards and Technology (NIST), 
               FIPS Publication 180-2: Secure Hash Standard, 1 August 
               2002. 
 
 
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   [SEC1]      Standards for Efficient Cryptography, "SEC 1: Elliptic 
               Curve Cryptography", Version 1.0, September 2000. 

   [X.680]     ITU-T Recommendation X.680: Information Technology - 
               Abstract Syntax Notation One, 1997. 

   [X.681] ITU-T Recommendation X.680: Information Technology - Abstract 
               Syntax Notation One: Information Object Spcification, 
               1997. 

6.2. Informative References 

   [RFC3279]   Polk, W., Housley, R. and L. Bassham, "Algorithm 
               Identifiers for the Internet X.509 Public Key 
               Infrastructure", RFC 3279, April 2002.  

Appendix A. ASN.1 Module 

   Appendix A.1 provides the normative ASN.1 definitions for the 
   structures described in this specification using ASN.1 as defined in 
   [X.680,X.681]. 

   To Be Supplied Later 
























 
 
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Author's 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 

 
 
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Full Copyright Statement 

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Acknowledgment 

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