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Versions: 00 01 02 03 04 05 06 08 RFC 6955

PKIX                                                           J. Schaad
Internet-Draft                                   Soaring Hawk Consulting
Obsoletes: 2875 (if approved)                          H. Prafullchandra
Intended status: Standards Track                                Hy-Trust
Expires: September 28, 2013                               March 27, 2013


             Diffie-Hellman Proof-of-Possession Algorithms
                    draft-schaad-pkix-rfc2875-bis-08

Abstract

   This document describes two methods for producing an integrity check
   value from a Diffie-Hellman key pair and one method for producing an
   integrity check value from an Elliptic Curve key pair.  This behavior
   is needed for such operations as creating the signature of a PKCS #10
   certification request.  These algorithms are designed to provide a
   proof-of-possession of the private key and not to be a general
   purpose signing algorithm.

   This document obsoletes RFC 2875.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on September 28, 2013.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
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   This document may contain material from IETF Documents or IETF
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   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Changes since RFC2875 . . . . . . . . . . . . . . . . . .   4
     1.2.  Requirements Terminology  . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Notation  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Static DH Proof-of-Possession Process . . . . . . . . . . . .   5
     4.1.  ASN.1 Encoding  . . . . . . . . . . . . . . . . . . . . .   7
   5.  Discrete Logarithm Signature  . . . . . . . . . . . . . . . .  10
     5.1.  Expanding the Digest Value  . . . . . . . . . . . . . . .  11
     5.2.  Signature Computation Algorithm . . . . . . . . . . . . .  12
     5.3.  Signature Verification Algorithm  . . . . . . . . . . . .  12
     5.4.  ASN.1 Encoding  . . . . . . . . . . . . . . . . . . . . .  13
   6.  Static ECDH Proof-of-Possession Process . . . . . . . . . . .  15
     6.1.  ASN.1 Encoding  . . . . . . . . . . . . . . . . . . . . .  17
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  20
   Appendix A.  ASN.1 Modules  . . . . . . . . . . . . . . . . . . .  20
     A.1.  2008 ASN.1 Module . . . . . . . . . . . . . . . . . . . .  21
     A.2.  1988 ASN.1 Module . . . . . . . . . . . . . . . . . . . .  25
   Appendix B.  Example of Static DH Proof-of-Possession . . . . . .  27
   Appendix C.  Example of Discrete Log Signature  . . . . . . . . .  35
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  40

1.  Introduction




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   Among the responsibilities of a Certificate Authority in issuing
   certificates is a requirement that it verifies the identity for the
   entity to which it is issuing a certificate and that it verifies that
   the private key for the public key to be placed in the certificate is
   in the possession of that entity.  The process of validating that the
   private key is held by the requester of the certificate is called
   Proof-of-Possession(POP).  Further details on why POP is important
   can be found in Appendix C of RFC 4211 [CRMF].

   This document is designed to deal with the problem of how to support
   POP for encryption-only keys.  PKCS #10 [RFC2986] and the Certificate
   Request Message Format (CRMF) [CRMF] both define syntaxes for
   certification requests.  However, while CRMF supports an alternative
   method to support POP for encryption-only keys, PKCS #10 does not.
   PKCS #10 assumes that the public key being requested for
   certification corresponds to an algorithm that is capable of
   producing a POP by a signature operation.  Diffie-Hellman (DH) and
   Elliptic Curve Diffie-Hellman (ECDH) are key agreement algorithms
   and, as such, cannot be directly used for signing or encryption.

   This document describes a set of three proof-of-possession
   algorithms.  Two methods use the key agreement process (one for
   Diffie-Hellman and one for Elliptic-Curve DH) to provide a shared
   secret as the basis of an integrity check value.  For these methods,
   the value is constructed for a specific recipient/verifier by using a
   public key of that verifier.  The third method uses a modified
   signature algorithm (for Diffie-Hellman).  This method allows for
   arbitrary verifiers.

   It should be noted that we did not create an algorithm that parallels
   ECDSA (Elliptical Curve Digital Signature Algorithm) as was done for
   DSA (Digital Signature Algorithm).  When using ECDH, the common
   practice is to use one of a set of predefined curves, each of these
   curves has been designed to be paired with one of the commonly used
   hash algorithm.  This differs in practice from the Diffie-Hellman
   case where the common practice is to generate a set of group
   parameters either on a single machine or for a given community and
   are aligned to encryption algorithms rather than hash algorithms.
   The implication is that, if a key has the ability to perform the
   modified DSA algorithm for ECDSA, it should be able to use the
   correct hash algorithm and perform the regular ECDSA signature
   algorithm with the correctly sized hash.









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1.1.  Changes since RFC2875

   The following changes have been made:

   o  The Static DH Proof-of-Possession algorithm has been re-written
      for parameterization of the hash algorithm and the message
      authentication code (MAC) algorithm.

   o  New instances of the static DH POP algorithm have been created
      using HMAC paired with the SHA-224, SHA-256, SHA-384 and SHA-512
      hash algorithms.  However the current SHA-1 algorithm remains
      identical.

   o  The Discrete Logarithm Signature algorithm has been re-written for
      parameterization of the hash algorithm.

   o  New instances of the Discrete Logarithm Signature have been
      created for the SHA-224, SHA-256, SHA-384, and SHA-512 hash
      functions.  However the current SHA-1 algorithm remains identical.

   o  A new Static ECDH Proof-of-Possession algorithm has been added.

   o  New instances of the Static ECDH POP algorithm has been created
      using HMAC paired with the SHA-224, SHA-256, SHA-384, and SHA-512
      hash functions.

1.2.  Requirements 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].

   When the words are in lower case they have their natural language
   meaning.

2.  Terminology

   The following definitions will be used in this document

   DH certificate = a certificate whose SubjectPublicKey is a DH public
   value and is signed with any signature algorithm (e.g., RSA or DSA).

   ECDH certificate = a certificate whose SubjectPublicKey is an ECDH
   public value and is signed with any signature algorithm (e.g., RSA or
   ECDSA).

   Proof-of-Possession (POP) is a means that provides a method for a
   second party to perform an algorithm to establish with some degree of



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   assurance that the first party does possess and has the ability to
   use a private key.  The reasoning behind doing POP can be found in
   Appendix C in [CRMF].

3.  Notation

   This section describes mathematical notations, conventions and
   symbols used throughout this document.

       a | b          : Concatenation of a and b
       a ^ b          : a raised to the power of b
       a mod b        : a modulo b
       a / b          : a divided by b using integer division
       a * b          : a times b
                        depending on context multiplication may be within
                        an Elliptic Curve or normal multiplication

       KDF(a)         : Key Derivation Function producing a value from a.
       MAC(a, b)      : Message Authentication Code function where
                        a is the key and b is the text
       LEFTMOST(a, b) : Return the b left most bits of a
       FLOOR(a)       : Return n where n is the largest integer such that
                        n <= a



   Details on how to implement the HMAC version of a MAC function used
   in this document can be found in RFC 2104 [RFC2104], RFC 6234
   [RFC6234] and RFC 4231 [RFC4231].

4.  Static DH Proof-of-Possession Process

   The Static DH POP algorithm is set up to use a key derivation
   function (KDF) and a message authentication code (MAC).  This
   algorithm requires that a common set of group parameters be used by
   both the creator and verifier of the POP value.

   The steps for creating a DH POP are:

   1.  An entity (E) chooses the group parameters for a DH key
       agreement.

       This is done simply by selecting the group parameters from a
       certificate for the recipient of the POP process.  A certificate
       with the correct group parameters has to be available.






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       Let the common DH parameters be g and p; and let the DH key-pair
       from the certificate be known as the Recipient key pair (Rpub and
       Rpriv).

       Rpub = g^x mod p (where x=Rpriv, the private DH value)

   2.  The entity generates a DH public/private key-pair using the group
       parameters from step 1.

       For an entity E:

       Epriv = DH private value = y
       Epub = DH public value = g^y mod p

   3.  The POP computation process will then consist of:

       a)  The value to be signed (text) is obtained.  (For a PKCS #10
             object, the value is the DER encoded
             certificationRequestInfo field represented as an octet
             string.)

       b)  A shared DH secret is computed, as follows,

             shared secret = ZZ = g^(x*y) mod p

             [This is done by the entity E as Rpub^y and by the
             Recipient as Epub^x, where Rpub is retrieved from the
             Recipient's DH certificate (or is provided in the protocol)
             and Epub is retrieved from the certification request.]

       c)  A temporary key K is derived from the shared secret ZZ as
             follows:

                K = KDF(LeadingInfo | ZZ | TrailingInfo)

                LeadingInfo ::= Subject Distinguished Name from
                recipient's certificate

                TrailingInfo ::= Issuer Distinguished Name from
                recipient's certificate

       d)  Using the defined MAC function, compute MAC(K, text).

   The POP verification process requires the Recipient to carry out
   steps (a) through (d) and then simply compare the result of step (d)
   with what it received as the signature component.  If they match then
   the following can be concluded:




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   a)  The Entity possesses the private key corresponding to the public
      key in the certification request because it needed the private key
      to calculate the shared secret; and

   b)  Only the Recipient that the entity sent the request to could
      actually verify the request because it would require its own
      private key to compute the same shared secret.  In the case where
      the recipient is a Certification Authority, this protects the
      Entity from rogue CAs.

4.1.  ASN.1 Encoding

   The algorithm outlined above allows for the use of an arbitrary hash
   function in computing the temporary key and the MAC algorithm.  In
   this specification we define object identifiers for the SHA-1,
   SHA-256, SHA-384 and SHA-512 hash values and use HMAC for the MAC
   algorithm.  The ASN.1 structures associated with the static Diffie-
   Hellman POP algorithm are:

      DhSigStatic ::= SEQUENCE {
          issuerAndSerial IssuerAndSerialNumber OPTIONAL,
          hashValue       MessageDigest
      }

      sa-dhPop-static-sha1-hmac-sha1 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-dhPop-static-sha1-hmac-sha1
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-dh-sig-hmac-sha1 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 3
      }

      id-dhPop-static-sha1-hmac-sha1 OBJECT IDENTIFIER ::=
           id-dh-sig-hmac-sha1

      sa-dhPop-static-sha224-hmac-sha224 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha224-hmac-sha224
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 15
      }



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      sa-dhPop-static-sha256-hmac-sha256 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha256-hmac-sha256
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 16
      }

      sa-dhPop-static-sha384-hmac-sha384 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha384-hmac-sha384
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 17
      }

      sa-dhPop-static-sha512-hmac-sha512 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha512-hmac-sha512
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 18
      }




   In the above ASN.1 the following items are defined:

   DhSigStatic
      This ASN.1 type structure holds the information describing the
      signature.  The structure has the following fields:

      issuerAndSerial
            This field contains the issuer name and serial number of the
            certificate from which the public key was obtained.  The
            issuerAndSerial field is omitted if the public key did not
            come from a certificate.




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      hashValue
            This field contains the result of the MAC operation in step
            3d.

   sa-dhPop-static-sha1-hmac-sha1
      An ASN.1 SIGNATURE-ALGORITHM object which associates together the
      information describing a signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-dhPop-static-sha1-hmac-sha1
      This OID identifies the Static DH POP algorithm that uses SHA-1 as
      the KDF and HMAC-SHA1 as the MAC function.  The new OID was
      created for naming consistency with the other OIDs defined here.
      The value of the OID is the same value as id-dh-sig-hmac-sha1
      which was defined in the previous version of this document
      [RFC2875].

   sa-dhPop-static-sha224-hmac-sha224
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-dhPop-static-sha224-hmac-sha224
      This OID identifies the Static DH POP algorithm that uses SHA-224
      as the KDF and HMAC-SHA224 as the MAC function.

   sa-dhPop-static-sha256-hmac-sha256
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-dhPop-static-sha256-hmac-sha256
      This OID identifies the Static DH POP algorithm that uses SHA-256
      as the KDF and HMAC-SHA256 as the MAC function.

   sa-dhPop-static-sha384-hmac-sha384
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-dhPop-static-sha384-hmac-sha384
      This OID identifies the Static DH POP algorithm that uses SHA-384
      as the KDF and HMAC-SHA384 as the MAC function.




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   sa-dhPop-static-sha512-hmac-sha512
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-dhPop-static-sha512-hmac-sha512
      This OID identifies the Static DH POP algorithm that uses SHA-512
      as the KDF and HMAC-SHA512 as the MAC function.

5.  Discrete Logarithm Signature

   When a single set of parameters is used for a large group of keys,
   the chances that a collision will occur in the set of keys either by
   accident or design increases as the number of keys used increases.  A
   large number of keys from a single parameter set also encourages the
   use of brute force methods of attack as the entire set of keys in the
   parameters can be attacked in a single operation rather than having
   to attack each key parameter set individually.

   For this reason we need to create a proof-of-possession for Diffie-
   Hellman keys that does not require the use of a common set of
   parameters.

   This POP is based on the Digital Signature Algorithm, but we have
   removed the restrictions dealing with the hash and key sizes imposed
   by the [FIPS-186] standard.  The use of this method does impose some
   additional restrictions on the set of keys that may be used, however
   if the key generation algorithm documented in [RFC2631] is used the
   required restrictions are met.  The additional restrictions are the
   requirement for the existence of a q parameter.  Adding the q
   parameter is generally accepted as a good practice as it allows for
   checking of small subgroup attacks.

   The following definitions are used in the rest of this section:

   p is a large prime
   g = h^((p-1)/q) mod p ,
   where h is any integer 1 < h < p-1 such that h^((p-1)/q) mod p > 1
   (g has order q mod p)
   q is a large prime
   j is a large integer such that p = q*j + 1
   x is a randomly or pseudo-randomly generated integer with 1 < x < q
   y = g^x mod p
   HASH is a hash function such that
   b = the output size of HASH in bits

   Note: These definitions match the ones in [RFC2631].



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5.1.  Expanding the Digest Value

   Besides the addition of a q parameter, [FIPS-186] also imposes size
   restrictions on the parameters.  The length of q must be 160 bits
   (matching the output length of the SHA-1 digest algorithm) and the
   length of p must be 1024 bits.  The size restriction on p is
   eliminated in this document, but the size restriction on q is
   replaced with the requirement that q must be at least b bits in
   length.  (If the hash function is SHA-1, then b=160 bits and the size
   restriction on b is identical with that in [FIPS-186].)

   Given that there is not a random length-hashing algorithm, a hash
   value of the message will need to be derived such that the hash is in
   the range from 0 to q-1.  If the length of q is greater than b then a
   method must be provided to expand the hash.

   The method for expanding the digest value used in this section does
   not add any additional security beyond the b bits provided by the
   hash algorithm.  For this reason the hash algorithm should be the
   largest size possible to match q.  The value being signed is
   increased mainly to enhance the difficulty of reversing the signature
   process.

   This algorithm produces m, the value to be signed.

   Let L = the size of q (i.e., 2^L <= q < 2^(L+1)).
   Let M be the original message to be signed.
   Let b be the length of HASH output

   1.  Compute d = HASH(M), the digest of the original message.

   2.  If L == b then m = d.

   3.  If L > b then follow steps (a) through (d) below.

       a)  Set n = FLOOR(L / b)

       b)  Set m = d, the initial computed digest value.

       c)  For i = 0 to n - 1
             m = m | HASH(m)

       d)  m = LEFTMOST(m, L-1)

   Thus the final result of the process meets the criteria that 0 <= m <
   q.





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5.2.  Signature Computation Algorithm

   The signature algorithm produces the pair of values (r, s), which is
   the signature.  The signature is computed as follows:

   Given m, the value to be signed, as well as the parameters defined
   earlier in section 5.

   1.  Generate a random or pseudorandom integer k, such that 0 < k-1 <
       q.

   2.  Compute r = (g^k mod p) mod q.

   3.  If r is zero, repeat from step 1.

   4.  Compute s = ((k^-1) * (m + x*r)) mod q.

   5.  If s is zero, repeat from step 1.

5.3.  Signature Verification Algorithm

   The signature verification process is far more complicated than is
   normal for the Digital Signature Algorithm, as some assumptions about
   the validity of parameters cannot be taken for granted.

   Given a value m to be validated, the signature value pair (r, s) and
   the parameters for the key.

   1.  Perform a strong verification that p is a prime number.

   2.  Perform a strong verification that q is a prime number.

   3.  Verify that q is a factor of p-1, if any of the above checks fail
       then the signature cannot be verified and must be considered a
       failure.

   4.  Verify that r and s are in the range [1, q-1].

   5.  Compute w = (s^-1) mod q.

   6.  Compute u1 = m*w mod q.

   7.  Compute u2 = r*w mod q.

   8.  Compute v = ((g^u1 * y^u2) mod p) mod q.

   9.  Compare v and r, if they are the same then the signature verified
       correctly.



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5.4.  ASN.1 Encoding

   The signature algorithm is parameterized by the hash algorithm.  The
   ASN.1 structures associated with the Discrete Logarithm Signature
   algorithm are:

      sa-dhPop-SHA1 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dh-pop
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha1 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha1 OBJECT IDENTIFIER ::= id-alg-dh-pop

      id-alg-dh-pop OBJECT IDENTIFIER ::= { id-pkix id-alg(6) 4 }

      sa-dhPop-sha224 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha224
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha224 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 5
      }

      sa-dhPop-sha256 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha256
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha256 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 6
      }

      sa-dhPop-sha384 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha384
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha384 }
         PUBLIC-KEYS { pk-dh }



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      }

      id-alg-dhPop-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 7
      }

      sa-dhPop-sha512 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha512
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha512 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 8
      }


   In the above ASN.1 the following items are defined:

   sa-dhPop-sha1
      A SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DSA-Sig-Value represents the signature value and the parameters
      DomainParameters SHOULD be omitted in the signature, but MUST be
      present in the associated key request.

   id-alg-dhPop-sha1
      This OID identifies the discrete logarithm signature using SHA-1
      as the hash algorithm.  The new OID was created for naming
      consistency with the others defined here.  The value of the OID is
      the same as id-alg-dh-pop which was defined in the previous
      version of this document [RFC2875].

   sa-dhPop-sha224
      A SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DSA-Sig-Value represents the signature value and the parameters
      DomainParameters SHOULD be omitted in the signature, but MUST be
      present in the associated key request.

   id-alg-dhPop-sha224
      This OID identifies the discrete logarithm signature using SHA-224
      as the hash algorithm.

   sa-dhPop-sha256




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      A SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DSA-Sig-Value represents the signature value and the parameters
      DomainParameters SHOULD be omitted in the signature, but MUST be
      present in the associated key request.

   id-alg-dhPop-sha256
      This OID identifies the discrete logarithm signature using SHA-256
      as the hash algorithm.

   sa-dhPop-sha384
      A SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DSA-Sig-Value represents the signature value and the parameters
      DomainParameters SHOULD be omitted in the signature, but MUST be
      present in the associated key request.

   id-alg-dhPop-sha384
      This OID identifies the discrete logarithm signature using SHA-384
      as the hash algorithm.

   sa-dhPop-sha512
      A SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DSA-Sig-Value represents the signature value and the parameters
      DomainParameters SHOULD be omitted in the signature, but MUST be
      present in the associated key request.

   id-alg-dhPop-sha512
      This OID identifies the discrete logarithm signature using SHA-512
      as the hash algorithm.

6.  Static ECDH Proof-of-Possession Process

   The Static ECDH POP algorithm is set up to use a key derivation
   function (KDF) and a message authentication code (MAC).  This
   algorithm requires that a common set of group parameters be used by
   both the creator and verifier of the POP value.  Full details of how
   Elliptic Curve Cryptography works can be found in RFC 6090 [RFC6090].

   The steps for creating an ECDH POP are:

   1.  An entity (E) chooses the group parameters for an ECDH key
       agreement.

       This is done simply by selecting the group parameters from a
       certificate for the recipient of the POP process.  A certificate
       with the correct group parameters has to be available.



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       The ECDH parameters can be identified either by a named group or
       by a set of curve parameters.  Section 2.3.5 of RFC 3279
       [RFC3279] documents how the parameters are encoded for PKIX
       certificates.  For PKIX-based applications, the parameters will
       almost always be defined by a named group.  Designate G as the
       group from the ECDH parameters.  Let the ECDH key-pair associated
       with the certificate be known as the Recipient key pair (Rpub and
       Rpriv).

       Rpub = Rpriv * G

   2.  The entity generates an ECDH public/private key-pair using the
       parameters from step 1.

       For an entity E:

       Epriv = Entity private value
       Epub = ECDH public point = Epriv * G

   3.  The POP computation process will then consist of:

       a)  The value to be signed (text) is obtained.  (For a PKCS #10
             object, the value is the DER encoded
             certificationRequestInfo field represented as an octet
             string.)

       b)  A shared ECDH secret is computed, as follows,

             shared secret point (x, y) = Epriv * Rpub = Rpriv * Epub

             shared secret value ZZ is the x coordinate of the computed
             point

       c)  A temporary key K is derived from the shared secret ZZ as
             follows:

             K = KDF(LeadingInfo | ZZ | TrailingInfo)

             LeadingInfo ::= Subject Distinguished Name from certificate
             TrailingInfo ::= Issuer Distinguished Name from certificate

       d)  Compute MAC(K, text).

   The POP verification process requires the Recipient to carry out
   steps (a) through (d) and then simply compare the result of step (d)
   with what it received as the signature component.  If they match then
   the following can be concluded:




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   a)  The Entity possesses the private key corresponding to the public
      key in the certification request because it needed the private key
      to calculate the shared secret; and

   b)  Only the Recipient that the entity sent the request to could
      actually verify the request because it would require its own
      private key to compute the same shared secret.  In the case where
      the recipient is a Certification Authority, this protects the
      Entity from rogue CAs.

6.1.  ASN.1 Encoding

   The algorithm outlined above allows for the use of an arbitrary hash
   function in computing the temporary key and the MAC value.  In this
   specification we defined object identifiers for the SHA-1 and SHA-256
   hash values.  The ASN.1 structures associated with the static ECDH
   POP algorithm are:

      id-alg-ecdhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 25
      }

      sa-ecdhPop-sha224-hmac-sha224 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha224-hmac-sha224
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }

      id-alg-ecdhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 26
      }

      sa-ecdhPop-sha256-hmac-sha256 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha256-hmac-sha256
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }

      id-alg-ecdhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 27
      }

      sa-ecdhPop-sha384-hmac-sha384 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha384-hmac-sha384
         VALUE DhSigStatic
         PARAMS ARE absent



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         PUBLIC-KEYS { pk-ec }
      }

      id-alg-ecdhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 28
      }

      sa-ecdhPop-sha512-hmac-sha512 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha512-hmac-sha512
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }


   In the above ASN.1 the following items are defined:

   sa-ecdhPop-static-sha224-hmac-sha224
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-ecdhPop-static-sha224-hmac-sha224
      This OID identifies the Static ECDH POP algorithm that uses
      SHA-224 as the KDF and HMAC-SHA224 as the MAC function.

   sa-ecdhPop-static-sha256-hmac-sha256
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-ecdhPop-static-sha256-hmac-sha256
      This OID identifies the Static ECDH POP algorithm that uses
      SHA-256 as the KDF and HMAC-SHA256 as the MAC function.

   sa-ecdhPop-static-sha384-hmac-sha384
      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-ecdhPop-static-sha384-hmac-sha384
      This OID identifies the Static ECDH POP algorithm that uses
      SHA-384 as the KDF and HMAC-SHA384 as the MAC function.

   sa-ecdhPop-static-sha512-hmac-sha512



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      An ASN.1 SIGNATURE-ALGORITHM object that associates together the
      information describing this signature algorithm.  The structure
      DhSigStatic represents the signature value and the parameters MUST
      be absent.

   id-ecdhPop-static-sha512-hmac-sha512
      This OID identifies the Static ECDH POP algorithm that uses
      SHA-512 as the KDF and HMAC-SHA512 as the MAC function.

7.  Security Considerations

   None of the algorithms defined in this document are meant for use in
   general purpose situations.  These algorithms are designed and
   purposed solely for use in doing Proof-of-Possession with PKCS#10 and
   CRMF constructs.

   In the static DH POP and static ECDH POP algorithms, an appropriate
   value can be produced by either party.  Thus these algorithms only
   provide integrity and not origination service.  The Discrete
   Logarithm algorithm provides both integrity checking and origination
   checking.

   All the security in this system is provided by the secrecy of the
   private keying material.  If either sender or recipient private keys
   are disclosed, all messages sent or received using that key are
   compromised.  Similarly, loss of the private key results in an
   inability to read messages sent using that key.

   Selection of parameters can be of paramount importance.  In the
   selection of parameters one must take into account the community/
   group of entities that one wishes to be able to communicate with.  In
   choosing a set of parameters one must also be sure to avoid small
   groups.  [FIPS-186] Appendixes 2 and 3 contain information on the
   selection of parameters for DH.  [RFC6090] Section 10 contains
   information on the selection of parameter for ECC.  The practices
   outlined in these documents will lead to better selection of
   parameters.

8.  IANA Considerations

   This document contains no IANA considerations.

9.  References

9.1.  Normative References






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   [RFC2104]  Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
              Hashing for Message Authentication", RFC 2104, February
              1997.

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

   [RFC2631]  Rescorla, E., "Diffie-Hellman Key Agreement Method", RFC
              2631, June 1999.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              November 2000.

   [RFC4231]  Nystrom, M., "Identifiers and Test Vectors for HMAC-
              SHA-224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512",
              RFC 4231, December 2005.

   [RFC6234]  Eastlake, D. and T. Hansen, "US Secure Hash Algorithms
              (SHA and SHA-based HMAC and HKDF)", RFC 6234, May 2011.

9.2.  Informative References

   [CRMF]     Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              September 2005.

   [FIPS-186]
              , "Digital Signature Standard", Federal Information
              Processing Standards Publication 186, May 1994.

   [RFC2875]  Prafullchandra, H. and J. Schaad, "Diffie-Hellman Proof-
              of-Possession Algorithms", RFC 2875, July 2000.

   [RFC3279]  Bassham, L., Polk, W., and R. Housley, "Algorithms and
              Identifiers for the Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 3279, April 2002.

   [RFC5912]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
              Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
              June 2010.

   [RFC6090]  McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic
              Curve Cryptography Algorithms", RFC 6090, February 2011.

Appendix A.  ASN.1 Modules




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A.1.  2008 ASN.1 Module

   This appendix contains an ASN.1 module which is conformant with the
   2008 version of ASN.1.  This module references the object classes
   defined by [RFC5912] to more completely describe all of the
   associations between the elements defined in this document.  Where a
   difference exists between the module in this section and the 1988
   module, the 2008 module is the definitive module.

   DH-Sign
      { iso(1) identified-organization(3) dod(6) internet(1)
        security(5) mechanisms(5) pkix(7) id-mod(0)
        id-mod-dhSign-2012-08(80) }
   DEFINITIONS IMPLICIT TAGS ::=

   BEGIN
   --EXPORTS ALL
   -- The types and values defined in this module are exported for use
   -- in the other ASN.1 modules. Other applications may use them
   -- for their own purposes.

   IMPORTS
      SIGNATURE-ALGORITHM
      FROM AlgorithmInformation-2009
         { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
          id-mod-algorithmInformation-02(58) }

      IssuerAndSerialNumber, MessageDigest
      FROM CryptographicMessageSyntax-2010
         { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
           pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) }

      DSA-Sig-Value, DomainParameters, ECDSA-Sig-Value,
      mda-sha1, mda-sha224, mda-sha256, mda-sha384, mda-sha512,
      pk-dh, pk-ec
      FROM PKIXAlgs-2009
         { iso(1) identified-organization(3) dod(6) internet(1)
           security(5) mechanisms(5) pkix(7) id-mod(0)
           id-mod-pkix1-algorithms2008-02(56) }

      id-pkix
      FROM PKIX1Explicit-2009
         { iso(1) identified-organization(3) dod(6) internet(1)
           security(5) mechanisms(5) pkix(7) id-mod(0)
           id-mod-pkix1-explicit-02(51) };

      DhSigStatic ::= SEQUENCE {



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          issuerAndSerial IssuerAndSerialNumber OPTIONAL,
          hashValue       MessageDigest
      }

      sa-dhPop-static-sha1-hmac-sha1 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-dhPop-static-sha1-hmac-sha1
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-dh-sig-hmac-sha1 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 3
      }

      id-dhPop-static-sha1-hmac-sha1 OBJECT IDENTIFIER ::=
           id-dh-sig-hmac-sha1

      sa-dhPop-static-sha224-hmac-sha224 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha224-hmac-sha224
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 15
      }

      sa-dhPop-static-sha256-hmac-sha256 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha256-hmac-sha256
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 16
      }

      sa-dhPop-static-sha384-hmac-sha384 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha384-hmac-sha384
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {



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           id-pkix id-alg(6) 17
      }

      sa-dhPop-static-sha512-hmac-sha512 SIGNATURE-ALGORITHM ::= {
           IDENTIFIER id-alg-dhPop-static-sha512-hmac-sha512
           VALUE DhSigStatic
           PARAMS ARE absent
           PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 18
      }




      sa-dhPop-SHA1 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dh-pop
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha1 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha1 OBJECT IDENTIFIER ::= id-alg-dh-pop

      id-alg-dh-pop OBJECT IDENTIFIER ::= { id-pkix id-alg(6) 4 }

      sa-dhPop-sha224 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha224
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha224 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 5
      }

      sa-dhPop-sha256 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha256
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha256 }
         PUBLIC-KEYS { pk-dh }
      }



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      id-alg-dhPop-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 6
      }

      sa-dhPop-sha384 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha384
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha384 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 7
      }

      sa-dhPop-sha512 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-dhPop-sha512
         VALUE DSA-Sig-Value
         PARAMS TYPE DomainParameters ARE preferredAbsent
         HASHES { mda-sha512 }
         PUBLIC-KEYS { pk-dh }
      }

      id-alg-dhPop-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 8
      }

      id-alg-ecdhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 25
      }

      sa-ecdhPop-sha224-hmac-sha224 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha224-hmac-sha224
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }

      id-alg-ecdhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 26
      }

      sa-ecdhPop-sha256-hmac-sha256 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha256-hmac-sha256
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }



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      }

      id-alg-ecdhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 27
      }

      sa-ecdhPop-sha384-hmac-sha384 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha384-hmac-sha384
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }

      id-alg-ecdhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
         id-pkix id-alg(6) 28
      }

      sa-ecdhPop-sha512-hmac-sha512 SIGNATURE-ALGORITHM ::= {
         IDENTIFIER id-alg-ecdhPop-static-sha512-hmac-sha512
         VALUE DhSigStatic
         PARAMS ARE absent
         PUBLIC-KEYS { pk-ec }
      }


   END


A.2.  1988 ASN.1 Module

   This appendix contains an ASN.1 module which is conformant with the
   1988 version of ASN.1 represents an informational version of the
   ASN.1 module for this document.  Where a difference exists between
   the module in this section and the 2008 module, the 2008 module is
   the definitive module.

   DH-Sign
      { iso(1) identified-organization(3) dod(6) internet(1)
        security(5) mechanisms(5) pkix(7) id-mod(0)
        id-mod-dhSign-2012-88(79) }
   DEFINITIONS IMPLICIT TAGS ::=

   BEGIN
   --EXPORTS ALL
   -- The types and values defined in this module are exported for use
   -- in the other ASN.1 modules. Other applications may use them
   -- for their own purposes.




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   IMPORTS
      IssuerAndSerialNumber, MessageDigest
      FROM CryptographicMessageSyntax2004
         { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
           pkcs-9(9) smime(16) modules(0) cms-2004(24) }

      id-pkix
      FROM PKIX1Explicit88
         { iso(1) identified-organization(3) dod(6) internet(1)
           security(5) mechanisms(5) pkix(7) id-mod(0)
           id-pkix1-explicit(18) }

      Dss-Sig-Value, DomainParameters
      FROM PKIX1Algorithms88
         { iso(1) identified-organization(3) dod(6) internet(1)
           security(5) mechanisms(5) pkix(7) id-mod(0)
           id-mod-pkix1-algorithms(17) };

      id-dh-sig-hmac-sha1 OBJECT IDENTIFIER ::= {id-pkix id-alg(6) 3}

      DhSigStatic ::= SEQUENCE {
          issuerAndSerial IssuerAndSerialNumber OPTIONAL,
          hashValue       MessageDigest
      }

      id-alg-dh-pop OBJECT IDENTIFIER ::= { id-pkix id-alg(6) 4 }

      id-dhPop-static-sha1-hmac-sha1 OBJECT IDENTIFIER ::=
           id-dh-sig-hmac-sha1

      id-alg-dhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 15 }

      id-alg-dhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 16 }

      id-alg-dhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 17 }

      id-alg-dhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 18 }


      id-alg-dhPop-sha1 OBJECT IDENTIFIER ::= id-alg-dh-pop

      id-alg-dhPop-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 5 }




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      id-alg-dhPop-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 6 }

      id-alg-dhPop-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 7 }

      id-alg-dhPop-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 8 }


      id-alg-ecdhPop-static-sha224-hmac-sha224 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 25 }

      id-alg-ecdhPop-static-sha256-hmac-sha256 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 26 }

      id-alg-ecdhPop-static-sha384-hmac-sha384 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 27 }

      id-alg-ecdhPop-static-sha512-hmac-sha512 OBJECT IDENTIFIER ::= {
           id-pkix id-alg(6) 28 }


   END


Appendix B.  Example of Static DH Proof-of-Possession

   The following example follows the steps described earlier in section
   4.

   Step 1: Establishing common Diffie-Hellman parameters.  Assume the
   parameters are as in the DER encoded certificate.  The certificate
   contains a DH public key signed by a CA with a DSA signing key.

     0 30 939: SEQUENCE {
     4 30 872:   SEQUENCE {
     8 A0   3:     [0] {
    10 02   1:       INTEGER 2
             :       }
    13 02   6:     INTEGER
             :       00 DA 39 B6 E2 CB
    21 30  11:     SEQUENCE {
    23 06   7:       OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3)
    32 05   0:       NULL
             :       }
    34 30  72:     SEQUENCE {
    36 31  11:       SET {



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    38 30   9:         SEQUENCE {
    40 06   3:           OBJECT IDENTIFIER countryName (2 5 4 6)
    45 13   2:           PrintableString 'US'
             :           }
             :         }
    49 31  17:       SET {
    51 30  15:         SEQUENCE {
    53 06   3:           OBJECT IDENTIFIER organizationName (2 5 4 10)
    58 13   8:           PrintableString 'XETI Inc'
             :           }
             :         }
    68 31  16:       SET {
    70 30  14:         SEQUENCE {
    72 06   3:           OBJECT IDENTIFIER organizationalUnitName (2 5 4
                                   11)
    77 13   7:           PrintableString 'Testing'
             :           }
             :         }
    86 31  20:       SET {
    88 30  18:         SEQUENCE {
    90 06   3:           OBJECT IDENTIFIER commonName (2 5 4 3)
    95 13  11:           PrintableString 'Root DSA CA'
             :           }
             :         }
             :       }
   108 30  30:     SEQUENCE {
   110 17  13:       UTCTime '990914010557Z'
   125 17  13:       UTCTime '991113010557Z'
             :       }
   140 30  70:     SEQUENCE {
   142 31  11:       SET {
   144 30   9:         SEQUENCE {
   146 06   3:           OBJECT IDENTIFIER countryName (2 5 4 6)
   151 13   2:           PrintableString 'US'
             :           }
             :         }
   155 31  17:       SET {
   157 30  15:         SEQUENCE {
   159 06   3:           OBJECT IDENTIFIER organizationName (2 5 4 10)
   164 13   8:           PrintableString 'XETI Inc'
             :           }
             :         }
   174 31  16:       SET {
   176 30  14:         SEQUENCE {
   178 06   3:           OBJECT IDENTIFIER organizationalUnitName (2 5 4
                                   11)
   183 13   7:           PrintableString 'Testing'
             :           }



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             :         }
   192 31  18:       SET {
   194 30  16:         SEQUENCE {
   196 06   3:           OBJECT IDENTIFIER commonName (2 5 4 3)
   201 13   9:           PrintableString 'DH TestCA'
             :           }
             :         }
             :       }
   212 30 577:     SEQUENCE {
   216 30 438:       SEQUENCE {
   220 06   7:         OBJECT IDENTIFIER dhPublicKey (1 2 840 10046 2 1)
   229 30 425:         SEQUENCE {
   233 02 129:           INTEGER
             :             00 94 84 E0 45 6C 7F 69 51 62 3E 56 80 7C 68 E7
             :             C5 A9 9E 9E 74 74 94 ED 90 8C 1D C4 E1 4A 14 82
             :             F5 D2 94 0C 19 E3 B9 10 BB 11 B9 E5 A5 FB 8E 21
             :             51 63 02 86 AA 06 B8 21 36 B6 7F 36 DF D1 D6 68
             :             5B 79 7C 1D 5A 14 75 1F 6A 93 75 93 CE BB 97 72
             :             8A F0 0F 23 9D 47 F6 D4 B3 C7 F0 F4 E6 F6 2B C2
             :             32 E1 89 67 BE 7E 06 AE F8 D0 01 6B 8B 2A F5 02
             :             D7 B6 A8 63 94 83 B0 1B 31 7D 52 1A DE E5 03 85
             :             27
   365 02 128:           INTEGER
             :             26 A6 32 2C 5A 2B D4 33 2B 5C DC 06 87 53 3F 90
             :             06 61 50 38 3E D2 B9 7D 81 1C 12 10 C5 0C 53 D4
             :             64 D1 8E 30 07 08 8C DD 3F 0A 2F 2C D6 1B 7F 57
             :             86 D0 DA BB 6E 36 2A 18 E8 D3 BC 70 31 7A 48 B6
             :             4E 18 6E DD 1F 22 06 EB 3F EA D4 41 69 D9 9B DE
             :             47 95 7A 72 91 D2 09 7F 49 5C 3B 03 33 51 C8 F1
             :             39 9A FF 04 D5 6E 7E 94 3D 03 B8 F6 31 15 26 48
             :             95 A8 5C DE 47 88 B4 69 3A 00 A7 86 9E DA D1 CD
   496 02  33:           INTEGER
             :             00 E8 72 FA 96 F0 11 40 F5 F2 DC FD 3B 5D 78 94
             :             B1 85 01 E5 69 37 21 F7 25 B9 BA 71 4A FC 60 30
             :             FB
   531 02  97:           INTEGER
             :             00 A3 91 01 C0 A8 6E A4 4D A0 56 FC 6C FE 1F A7
             :             B0 CD 0F 94 87 0C 25 BE 97 76 8D EB E5 A4 09 5D
             :             AB 83 CD 80 0B 35 67 7F 0C 8E A7 31 98 32 85 39
             :             40 9D 11 98 D8 DE B8 7F 86 9B AF 8D 67 3D B6 76
             :             B4 61 2F 21 E1 4B 0E 68 FF 53 3E 87 DD D8 71 56
             :             68 47 DC F7 20 63 4B 3C 5F 78 71 83 E6 70 9E E2
             :             92
   630 30  26:           SEQUENCE {
   632 03  21:             BIT STRING 0 unused bits
             :             1C D5 3A 0D 17 82 6D 0A 81 75 81 46 10 8E 3E DB
             :             09 E4 98 34
   655 02   1:             INTEGER 55



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             :             }
             :           }
             :         }
   658 03 132:       BIT STRING 0 unused bits
             :         02 81 80 5F CF 39 AD 62 CF 49 8E D1 CE 66 E2 B1
             :         E6 A7 01 4D 05 C2 77 C8 92 52 42 A9 05 A4 DB E0
             :         46 79 50 A3 FC 99 3D 3D A6 9B A9 AD BC 62 1C 69
             :         B7 11 A1 C0 2A F1 85 28 F7 68 FE D6 8F 31 56 22
             :         4D 0A 11 6E 72 3A 02 AF 0E 27 AA F9 ED CE 05 EF
             :         D8 59 92 C0 18 D7 69 6E BD 70 B6 21 D1 77 39 21
             :         E1 AF 7A 3A CF 20 0A B4 2C 69 5F CF 79 67 20 31
             :         4D F2 C6 ED 23 BF C4 BB 1E D1 71 40 2C 07 D6 F0
             :         8F C5 1A
             :       }
   793 A3  85:     [3] {
   795 30  83:       SEQUENCE {
   797 30  29:         SEQUENCE {
   799 06   3:           OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14)
   804 04  22:           OCTET STRING
             :             04 14 80 DF 59 88 BF EB 17 E1 AD 5E C6 40 A3 42
             :             E5 AC D3 B4 88 78
             :           }
   828 30  34:         SEQUENCE {
   830 06   3:           OBJECT IDENTIFIER authorityKeyIdentifier (2 5 29
   35)
   835 01   1:           BOOLEAN TRUE
   838 04  24:           OCTET STRING
             :             30 16 80 14 6A 23 37 55 B9 FD 81 EA E8 4E D3 C9
             :             B7 09 E5 7B 06 E3 68 AA
             :           }
   864 30  14:         SEQUENCE {
   866 06   3:           OBJECT IDENTIFIER keyUsage (2 5 29 15)
   871 01   1:           BOOLEAN TRUE
   874 04   4:           OCTET STRING
             :             03 02 03 08
             :           }
             :         }
             :       }
             :     }
   880 30  11:   SEQUENCE {
   882 06   7:     OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3)
   891 05   0:     NULL
             :     }
   893 03  48:   BIT STRING 0 unused bits
             :     30 2D 02 14 7C 6D D2 CA 1E 32 D1 30 2E 29 66 BC
             :     06 8B 60 C7 61 16 3B CA 02 15 00 8A 18 DD C1 83
             :     58 29 A2 8A 67 64 03 92 AB 02 CE 00 B5 94 6A
             :   }



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   Step 2.  End Entity/User generates a Diffie-Hellman key-pair using
   the parameters from the CA certificate.

   EE DH public key:

   Y: 13 63 A1 85 04 8C 46 A8 88 EB F4 5E A8 93 74 AE
      FD AE 9E 96 27 12 65 C4 4C 07 06 3E 18 FE 94 B8
      A8 79 48 BD 2E 34 B6 47 CA 04 30 A1 EC 33 FD 1A
      0B 2D 9E 50 C9 78 0F AE 6A EC B5 6B 6A BE B2 5C
      DA B2 9F 78 2C B9 77 E2 79 2B 25 BF 2E 0B 59 4A
      93 4B F8 B3 EC 81 34 AE 97 47 52 E0 A8 29 98 EC
      D1 B0 CA 2B 6F 7A 8B DB 4E 8D A5 15 7E 7E AF 33
      62 09 9E 0F 11 44 8C C1 8D A2 11 9E 53 EF B2 E8


   EE DH private key:

   X: 32 CC BD B4 B7 7C 44 26 BB 3C 83 42 6E 7D 1B 00
      86 35 09 71 07 A0 A4 76 B8 DB 5F EC 00 CE 6F C3


   Step 3.  Compute the shared secret ZZ

   56 b6 01 39 42 8e 09 16 30 b0 31 4d 12 90 af 03
   c7 92 65 c2 9c ba 88 bb 0a d5 94 02 ed 6f 54 cb
   22 e5 94 b4 d6 60 72 bc f6 a5 2b 18 8d df 28 72
   ac e0 41 dd 3b 03 2a 12 9e 5d bd 72 a0 1e fb 6b
   ee c5 b2 16 59 ee 12 00 3b c8 e0 cb c5 08 8e 2d
   40 5f 2d 37 62 8c 4f bb 49 76 69 3c 9e fc 2c f7
   f9 50 c1 b9 f7 01 32 4c 96 b9 c3 56 c0 2c 1b 77
   3f 2f 36 e8 22 c8 2e 07 76 d0 4f 7f aa d5 c0 59


   Step 4.  Compute K and the signature.

   LeadingInfo: DER encoded Subject/Requestor DN (as in the generated
   Certificate Signing Request)

     30 46 31 0B 30 09 06 03 55 04 06 13 02 55 53 31
     11 30 0F 06 03 55 04 0A 13 08 58 45 54 49 20 49
     6E 63 31 10 30 0E 06 03 55 04 0B 13 07 54 65 73
     74 69 6E 67 31 12 30 10 06 03 55 04 03 13 09 44
     48 20 54 65 73 74 43 41


   TrailingInfo: DER encoded Issuer/Recipient DN (from the certificate
   described in step 1)




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     30 48 31 0B 30 09 06 03 55 04 06 13 02 55 53 31
     11 30 0F 06 03 55 04 0A 13 08 58 45 54 49 20 49
     6E 63 31 10 30 0E 06 03 55 04 0B 13 07 54 65 73
     74 69 6E 67 31 14 30 12 06 03 55 04 03 13 0B 52
     6F 6F 74 20 44 53 41 20 43 41


   K:
     B1 91 D7 DB 4F C5 EF EF AC 9A C5 44 5A 6D 42 28
     DC 70 7B DA


   TBS: the "text" for computing the SHA-1 HMAC.

   30 82 02 98 02 01 00 30 4E 31 0B 30 09 06 03 55
   04 06 13 02 55 53 31 11 30 0F 06 03 55 04 0A 13
   08 58 45 54 49 20 49 6E 63 31 10 30 0E 06 03 55
   04 0B 13 07 54 65 73 74 69 6E 67 31 1A 30 18 06
   03 55 04 03 13 11 50 4B 49 58 20 45 78 61 6D 70
   6C 65 20 55 73 65 72 30 82 02 41 30 82 01 B6 06
   07 2A 86 48 CE 3E 02 01 30 82 01 A9 02 81 81 00
   94 84 E0 45 6C 7F 69 51 62 3E 56 80 7C 68 E7 C5
   A9 9E 9E 74 74 94 ED 90 8C 1D C4 E1 4A 14 82 F5
   D2 94 0C 19 E3 B9 10 BB 11 B9 E5 A5 FB 8E 21 51
   63 02 86 AA 06 B8 21 36 B6 7F 36 DF D1 D6 68 5B
   79 7C 1D 5A 14 75 1F 6A 93 75 93 CE BB 97 72 8A
   F0 0F 23 9D 47 F6 D4 B3 C7 F0 F4 E6 F6 2B C2 32
   E1 89 67 BE 7E 06 AE F8 D0 01 6B 8B 2A F5 02 D7
   B6 A8 63 94 83 B0 1B 31 7D 52 1A DE E5 03 85 27
   02 81 80 26 A6 32 2C 5A 2B D4 33 2B 5C DC 06 87
   53 3F 90 06 61 50 38 3E D2 B9 7D 81 1C 12 10 C5
   0C 53 D4 64 D1 8E 30 07 08 8C DD 3F 0A 2F 2C D6
   1B 7F 57 86 D0 DA BB 6E 36 2A 18 E8 D3 BC 70 31
   7A 48 B6 4E 18 6E DD 1F 22 06 EB 3F EA D4 41 69
   D9 9B DE 47 95 7A 72 91 D2 09 7F 49 5C 3B 03 33
   51 C8 F1 39 9A FF 04 D5 6E 7E 94 3D 03 B8 F6 31
   15 26 48 95 A8 5C DE 47 88 B4 69 3A 00 A7 86 9E
   DA D1 CD 02 21 00 E8 72 FA 96 F0 11 40 F5 F2 DC
   FD 3B 5D 78 94 B1 85 01 E5 69 37 21 F7 25 B9 BA
   71 4A FC 60 30 FB 02 61 00 A3 91 01 C0 A8 6E A4
   4D A0 56 FC 6C FE 1F A7 B0 CD 0F 94 87 0C 25 BE
   97 76 8D EB E5 A4 09 5D AB 83 CD 80 0B 35 67 7F
   0C 8E A7 31 98 32 85 39 40 9D 11 98 D8 DE B8 7F
   86 9B AF 8D 67 3D B6 76 B4 61 2F 21 E1 4B 0E 68
   FF 53 3E 87 DD D8 71 56 68 47 DC F7 20 63 4B 3C
   5F 78 71 83 E6 70 9E E2 92 30 1A 03 15 00 1C D5
   3A 0D 17 82 6D 0A 81 75 81 46 10 8E 3E DB 09 E4
   98 34 02 01 37 03 81 84 00 02 81 80 13 63 A1 85



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   04 8C 46 A8 88 EB F4 5E A8 93 74 AE FD AE 9E 96
   27 12 65 C4 4C 07 06 3E 18 FE 94 B8 A8 79 48 BD
   2E 34 B6 47 CA 04 30 A1 EC 33 FD 1A 0B 2D 9E 50
   C9 78 0F AE 6A EC B5 6B 6A BE B2 5C DA B2 9F 78
   2C B9 77 E2 79 2B 25 BF 2E 0B 59 4A 93 4B F8 B3
   EC 81 34 AE 97 47 52 E0 A8 29 98 EC D1 B0 CA 2B
   6F 7A 8B DB 4E 8D A5 15 7E 7E AF 33 62 09 9E 0F
   11 44 8C C1 8D A2 11 9E 53 EF B2 E8


   Certification Request:

     0 30 793: SEQUENCE {
     4 30 664:   SEQUENCE {
     8 02   1:     INTEGER 0
    11 30  78:     SEQUENCE {
    13 31  11:       SET {
    15 30   9:         SEQUENCE {
    17 06   3:           OBJECT IDENTIFIER countryName (2 5 4 6)
    22 13   2:           PrintableString 'US'
             :           }
             :         }
    26 31  17:       SET {
    28 30  15:         SEQUENCE {
    30 06   3:           OBJECT IDENTIFIER organizationName (2 5 4 10)
    35 13   8:           PrintableString 'XETI Inc'
             :           }
             :         }
    45 31  16:       SET {
    47 30  14:         SEQUENCE {
    49 06   3:           OBJECT IDENTIFIER organizationalUnitName (2 5 4
                                   11)
    54 13   7:           PrintableString 'Testing'
             :           }
             :         }
    63 31  26:       SET {
    65 30  24:         SEQUENCE {
    67 06   3:           OBJECT IDENTIFIER commonName (2 5 4 3)
    72 13  17:           PrintableString 'PKIX Example User'
             :           }
             :         }
             :       }
    91 30 577:     SEQUENCE {
    95 30 438:       SEQUENCE {
    99 06   7:         OBJECT IDENTIFIER dhPublicKey (1 2 840 10046 2 1)
   108 30 425:         SEQUENCE {
   112 02 129:           INTEGER
             :             00 94 84 E0 45 6C 7F 69 51 62 3E 56 80 7C 68 E7



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             :             C5 A9 9E 9E 74 74 94 ED 90 8C 1D C4 E1 4A 14 82
             :             F5 D2 94 0C 19 E3 B9 10 BB 11 B9 E5 A5 FB 8E 21
             :             51 63 02 86 AA 06 B8 21 36 B6 7F 36 DF D1 D6 68
             :             5B 79 7C 1D 5A 14 75 1F 6A 93 75 93 CE BB 97 72
             :             8A F0 0F 23 9D 47 F6 D4 B3 C7 F0 F4 E6 F6 2B C2
             :             32 E1 89 67 BE 7E 06 AE F8 D0 01 6B 8B 2A F5 02
             :             D7 B6 A8 63 94 83 B0 1B 31 7D 52 1A DE E5 03 85
             :             27
   244 02 128:           INTEGER
             :             26 A6 32 2C 5A 2B D4 33 2B 5C DC 06 87 53 3F 90
             :             06 61 50 38 3E D2 B9 7D 81 1C 12 10 C5 0C 53 D4
             :             64 D1 8E 30 07 08 8C DD 3F 0A 2F 2C D6 1B 7F 57
             :             86 D0 DA BB 6E 36 2A 18 E8 D3 BC 70 31 7A 48 B6
             :             4E 18 6E DD 1F 22 06 EB 3F EA D4 41 69 D9 9B DE
             :             47 95 7A 72 91 D2 09 7F 49 5C 3B 03 33 51 C8 F1
             :             39 9A FF 04 D5 6E 7E 94 3D 03 B8 F6 31 15 26 48
             :             95 A8 5C DE 47 88 B4 69 3A 00 A7 86 9E DA D1 CD
   375 02  33:           INTEGER
             :             00 E8 72 FA 96 F0 11 40 F5 F2 DC FD 3B 5D 78 94
             :             B1 85 01 E5 69 37 21 F7 25 B9 BA 71 4A FC 60 30
             :             FB
   410 02  97:           INTEGER
             :             00 A3 91 01 C0 A8 6E A4 4D A0 56 FC 6C FE 1F A7
             :             B0 CD 0F 94 87 0C 25 BE 97 76 8D EB E5 A4 09 5D
             :             AB 83 CD 80 0B 35 67 7F 0C 8E A7 31 98 32 85 39
             :             40 9D 11 98 D8 DE B8 7F 86 9B AF 8D 67 3D B6 76
             :             B4 61 2F 21 E1 4B 0E 68 FF 53 3E 87 DD D8 71 56
             :             68 47 DC F7 20 63 4B 3C 5F 78 71 83 E6 70 9E E2
             :             92
   509 30  26:           SEQUENCE {
   511 03  21:             BIT STRING 0 unused bits
             :               1C D5 3A 0D 17 82 6D 0A 81 75 81 46 10 8E 3E
             :               DB 09 E4 98 34
   534 02   1:             INTEGER 55
             :             }
             :           }
             :         }
   537 03 132:       BIT STRING 0 unused bits
             :         02 81 80 13 63 A1 85 04 8C 46 A8 88 EB F4 5E A8
             :         93 74 AE FD AE 9E 96 27 12 65 C4 4C 07 06 3E 18
             :         FE 94 B8 A8 79 48 BD 2E 34 B6 47 CA 04 30 A1 EC
             :         33 FD 1A 0B 2D 9E 50 C9 78 0F AE 6A EC B5 6B 6A
             :         BE B2 5C DA B2 9F 78 2C B9 77 E2 79 2B 25 BF 2E
             :         0B 59 4A 93 4B F8 B3 EC 81 34 AE 97 47 52 E0 A8
             :         29 98 EC D1 B0 CA 2B 6F 7A 8B DB 4E 8D A5 15 7E
             :         7E AF 33 62 09 9E 0F 11 44 8C C1 8D A2 11 9E 53
             :         EF B2 E8
             :       }



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             :     }
   672 30  12:   SEQUENCE {
   674 06   8:     OBJECT IDENTIFIER dh-sig-hmac-sha1 (1 3 6 1 5 5 7 6 3)
   684 05   0:     NULL
             :     }
   686 03 109:   BIT STRING 0 unused bits
             :     30 6A 30 52 30 48 31 0B 30 09 06 03 55 04 06 13
             :     02 55 53 31 11 30 0F 06 03 55 04 0A 13 08 58 45
             :     54 49 20 49 6E 63 31 10 30 0E 06 03 55 04 0B 13
             :     07 54 65 73 74 69 6E 67 31 14 30 12 06 03 55 04
             :     03 13 0B 52 6F 6F 74 20 44 53 41 20 43 41 02 06
             :     00 DA 39 B6 E2 CB 04 14 2D 05 77 FE 5E 8F 65 F5
             :     AF AD C9 5C 9B 02 C0 A8 88 29 61 63
             :   }


   Signature verification requires CA's private key, the CA certificate
   and the generated Certification Request.

   CA DH private key:

    x:  3E 5D AD FD E5 F4 6B 1B 61 5E 18 F9 0B 84 74 a7
        52 1E D6 92 BC 34 94 56 F3 0C BE DA 67 7A DD 7D


Appendix C.  Example of Discrete Log Signature

   Step 1.  Generate a Diffie-Hellman Key with length of q being 256
   bits.

      p:
        94 84 E0 45 6C 7F 69 51 62 3E 56 80 7C 68 E7 C5
        A9 9E 9E 74 74 94 ED 90 8C 1D C4 E1 4A 14 82 F5
        D2 94 0C 19 E3 B9 10 BB 11 B9 E5 A5 FB 8E 21 51
        63 02 86 AA 06 B8 21 36 B6 7F 36 DF D1 D6 68 5B
        79 7C 1D 5A 14 75 1F 6A 93 75 93 CE BB 97 72 8A
        F0 0F 23 9D 47 F6 D4 B3 C7 F0 F4 E6 F6 2B C2 32
        E1 89 67 BE 7E 06 AE F8 D0 01 6B 8B 2A F5 02 D7
        B6 A8 63 94 83 B0 1B 31 7D 52 1A DE E5 03 85 27

      q:
        E8 72 FA 96 F0 11 40 F5 F2 DC FD 3B 5D 78 94 B1
        85 01 E5 69 37 21 F7 25 B9 BA 71 4A FC 60 30 FB

      g:
        26 A6 32 2C 5A 2B D4 33 2B 5C DC 06 87 53 3F 90
        06 61 50 38 3E D2 B9 7D 81 1C 12 10 C5 0C 53 D4
        64 D1 8E 30 07 08 8C DD 3F 0A 2F 2C D6 1B 7F 57



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        86 D0 DA BB 6E 36 2A 18 E8 D3 BC 70 31 7A 48 B6
        4E 18 6E DD 1F 22 06 EB 3F EA D4 41 69 D9 9B DE
        47 95 7A 72 91 D2 09 7F 49 5C 3B 03 33 51 C8 F1
        39 9A FF 04 D5 6E 7E 94 3D 03 B8 F6 31 15 26 48
        95 A8 5C DE 47 88 B4 69 3A 00 A7 86 9E DA D1 CD

      j:
        A3 91 01 C0 A8 6E A4 4D A0 56 FC 6C FE 1F A7 B0
        CD 0F 94 87 0C 25 BE 97 76 8D EB E5 A4 09 5D AB
        83 CD 80 0B 35 67 7F 0C 8E A7 31 98 32 85 39 40
        9D 11 98 D8 DE B8 7F 86 9B AF 8D 67 3D B6 76 B4
        61 2F 21 E1 4B 0E 68 FF 53 3E 87 DD D8 71 56 68
        47 DC F7 20 63 4B 3C 5F 78 71 83 E6 70 9E E2 92

      y:
        5F CF 39 AD 62 CF 49 8E D1 CE 66 E2 B1 E6 A7 01
        4D 05 C2 77 C8 92 52 42 A9 05 A4 DB E0 46 79 50
        A3 FC 99 3D 3D A6 9B A9 AD BC 62 1C 69 B7 11 A1
        C0 2A F1 85 28 F7 68 FE D6 8F 31 56 22 4D 0A 11
        6E 72 3A 02 AF 0E 27 AA F9 ED CE 05 EF D8 59 92
        C0 18 D7 69 6E BD 70 B6 21 D1 77 39 21 E1 AF 7A
        3A CF 20 0A B4 2C 69 5F CF 79 67 20 31 4D F2 C6
        ED 23 BF C4 BB 1E D1 71 40 2C 07 D6 F0 8F C5 1A

      seed:
        1C D5 3A 0D 17 82 6D 0A 81 75 81 46 10 8E 3E DB
        09 E4 98 34

      C:
        00000037

      x:
        3E 5D AD FD E5 F4 6B 1B 61 5E 18 F9 0B 84 74 a7
        52 1E D6 92 BC 34 94 56 F3 0C BE DA 67 7A DD 7D


   Step 2.  Form the value to be signed and hash with SHA1.  The result
   of the hash for this example is:

     5f a2 69 b6 4b 22 91 22 6f 4c fe 68 ec 2b d1 c6
     d4 21 e5 2c


   Step 3.  The hash value needs to be expanded since |q| = 256.  This
   is done by hashing the hash with SHA1 and appending it to the
   original hash.  The value after this step is:





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     5f a2 69 b6 4b 22 91 22 6f 4c fe 68 ec 2b d1 c6
     d4 21 e5 2c 64 92 8b c9 5e 34 59 70 bd 62 40 ad
     6f 26 3b f7 1c a3 b2 cb


   Next the first 255 bits of this value are taken to be the resulting
   "hash" value.  Note in this case a shift of one bit right is done
   since the result is to be treated as an integer:

     2f d1 34 db 25 91 48 91 37 a6 7f 34 76 15 e8 e3
     6a 10 f2 96 32 49 45 e4 af 1a 2c b8 5e b1 20 56


   Step 4.  The signature value is computed.  In this case you get the
   values

      r:
        A1 B5 B4 90 01 34 6B A0 31 6A 73 F5 7D F6 5C 14
        43 52 D2 10 BF 86 58 87 F7 BC 6E 5A 77 FF C3 4B

      s:
        59 40 45 BC 6F 0D DC FF 9D 55 40 1E C4 9E 51 3D
        66 EF B2 FF 06 40 9A 39 68 75 81 F7 EC 9E BE A1


   The encoded signature value is then:

      30 45 02 21 00 A1 B5 B4 90 01 34 6B A0 31 6A 73
      F5 7D F6 5C 14 43 52 D2 10 BF 86 58 87 F7 BC 6E
      5A 77 FF C3 4B 02 20 59 40 45 BC 6F 0D DC FF 9D
      55 40 1E C4 9E 51 3D 66 EF B2 FF 06 40 9A 39 68
      75 81 F7 EC 9E BE A1

      Result:
        30 82 02 c2 30 82 02 67 02 01 00 30 1b 31 19 30
        17 06 03 55 04 03 13 10 49 45 54 46 20 50 4b 49
        58 20 53 41 4d 50 4c 45 30 82 02 41 30 82 01 b6
        06 07 2a 86 48 ce 3e 02 01 30 82 01 a9 02 81 81
        00 94 84 e0 45 6c 7f 69 51 62 3e 56 80 7c 68 e7
        c5 a9 9e 9e 74 74 94 ed 90 8c 1d c4 e1 4a 14 82
        f5 d2 94 0c 19 e3 b9 10 bb 11 b9 e5 a5 fb 8e 21
        51 63 02 86 aa 06 b8 21 36 b6 7f 36 df d1 d6 68
        5b 79 7c 1d 5a 14 75 1f 6a 93 75 93 ce bb 97 72
        8a f0 0f 23 9d 47 f6 d4 b3 c7 f0 f4 e6 f6 2b c2
        32 e1 89 67 be 7e 06 ae f8 d0 01 6b 8b 2a f5 02
        d7 b6 a8 63 94 83 b0 1b 31 7d 52 1a de e5 03 85
        27 02 81 80 26 a6 32 2c 5a 2b d4 33 2b 5c dc 06
        87 53 3f 90 06 61 50 38 3e d2 b9 7d 81 1c 12 10



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        c5 0c 53 d4 64 d1 8e 30 07 08 8c dd 3f 0a 2f 2c
        d6 1b 7f 57 86 d0 da bb 6e 36 2a 18 e8 d3 bc 70
        31 7a 48 b6 4e 18 6e dd 1f 22 06 eb 3f ea d4 41
        69 d9 9b de 47 95 7a 72 91 d2 09 7f 49 5c 3b 03
        33 51 c8 f1 39 9a ff 04 d5 6e 7e 94 3d 03 b8 f6
        31 15 26 48 95 a8 5c de 47 88 b4 69 3a 00 a7 86
        9e da d1 cd 02 21 00 e8 72 fa 96 f0 11 40 f5 f2
        dc fd 3b 5d 78 94 b1 85 01 e5 69 37 21 f7 25 b9
        ba 71 4a fc 60 30 fb 02 61 00 a3 91 01 c0 a8 6e
        a4 4d a0 56 fc 6c fe 1f a7 b0 cd 0f 94 87 0c 25
        be 97 76 8d eb e5 a4 09 5d ab 83 cd 80 0b 35 67
        7f 0c 8e a7 31 98 32 85 39 40 9d 11 98 d8 de b8
        7f 86 9b af 8d 67 3d b6 76 b4 61 2f 21 e1 4b 0e
        68 ff 53 3e 87 dd d8 71 56 68 47 dc f7 20 63 4b
        3c 5f 78 71 83 e6 70 9e e2 92 30 1a 03 15 00 1c
        d5 3a 0d 17 82 6d 0a 81 75 81 46 10 8e 3e db 09
        e4 98 34 02 01 37 03 81 84 00 02 81 80 5f cf 39
        ad 62 cf 49 8e d1 ce 66 e2 b1 e6 a7 01 4d 05 c2
        77 c8 92 52 42 a9 05 a4 db e0 46 79 50 a3 fc 99
        3d 3d a6 9b a9 ad bc 62 1c 69 b7 11 a1 c0 2a f1
        85 28 f7 68 fe d6 8f 31 56 22 4d 0a 11 6e 72 3a
        02 af 0e 27 aa f9 ed ce 05 ef d8 59 92 c0 18 d7
        69 6e bd 70 b6 21 d1 77 39 21 e1 af 7a 3a cf 20
        0a b4 2c 69 5f cf 79 67 20 31 4d f2 c6 ed 23 bf
        c4 bb 1e d1 71 40 2c 07 d6 f0 8f c5 1a a0 00 30
        0c 06 08 2b 06 01 05 05 07 06 04 05 00 03 47 00
        30 44 02 20 54 d9 43 8d 0f 9d 42 03 d6 09 aa a1
        9a 3c 17 09 ae bd ee b3 d1 a0 00 db 7d 8c b8 e4
        56 e6 57 7b 02 20 44 89 b1 04 f5 40 2b 5f e7 9c
        f9 a4 97 50 0d ad c3 7a a4 2b b2 2d 5d 79 fb 38
        8a b4 df bb 88 bc


   Decoded Version of result:

     0 30  707: SEQUENCE {
     4 30  615:   SEQUENCE {
     8 02    1:     INTEGER 0
    11 30   27:     SEQUENCE {
    13 31   25:       SET {
    15 30   23:         SEQUENCE {
    17 06    3:           OBJECT IDENTIFIER commonName (2 5 4 3)
    22 13   16:           PrintableString 'IETF PKIX SAMPLE'
              :           }
              :         }
              :       }
    40 30  577:     SEQUENCE {
    44 30  438:       SEQUENCE {



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Internet-Draft             DH POP Algorithms                  March 2013


    48 06    7:         OBJECT IDENTIFIER dhPublicNumber (1 2 840 10046 2
                                    1)
    57 30  425:         SEQUENCE {
    61 02  129:           INTEGER
              :            00 94 84 E0 45 6C 7F 69 51 62 3E 56 80 7C 68 E7
              :            C5 A9 9E 9E 74 74 94 ED 90 8C 1D C4 E1 4A 14 82
              :            F5 D2 94 0C 19 E3 B9 10 BB 11 B9 E5 A5 FB 8E 21
              :            51 63 02 86 AA 06 B8 21 36 B6 7F 36 DF D1 D6 68
              :            5B 79 7C 1D 5A 14 75 1F 6A 93 75 93 CE BB 97 72
              :            8A F0 0F 23 9D 47 F6 D4 B3 C7 F0 F4 E6 F6 2B C2
              :            32 E1 89 67 BE 7E 06 AE F8 D0 01 6B 8B 2A F5 02
              :            D7 B6 A8 63 94 83 B0 1B 31 7D 52 1A DE E5 03 85
              :            27
   193 02  128:           INTEGER
              :            26 A6 32 2C 5A 2B D4 33 2B 5C DC 06 87 53 3F 90
              :            06 61 50 38 3E D2 B9 7D 81 1C 12 10 C5 0C 53 D4
              :            64 D1 8E 30 07 08 8C DD 3F 0A 2F 2C D6 1B 7F 57
              :            86 D0 DA BB 6E 36 2A 18 E8 D3 BC 70 31 7A 48 B6
              :            4E 18 6E DD 1F 22 06 EB 3F EA D4 41 69 D9 9B DE
              :            47 95 7A 72 91 D2 09 7F 49 5C 3B 03 33 51 C8 F1
              :            39 9A FF 04 D5 6E 7E 94 3D 03 B8 F6 31 15 26 48
              :            95 A8 5C DE 47 88 B4 69 3A 00 A7 86 9E DA D1 CD
   324 02   33:           INTEGER
              :            00 E8 72 FA 96 F0 11 40 F5 F2 DC FD 3B 5D 78 94
              :            B1 85 01 E5 69 37 21 F7 25 B9 BA 71 4A FC 60 30
              :            FB
   359 02   97:           INTEGER
              :            00 A3 91 01 C0 A8 6E A4 4D A0 56 FC 6C FE 1F A7
              :            B0 CD 0F 94 87 0C 25 BE 97 76 8D EB E5 A4 09 5D
              :            AB 83 CD 80 0B 35 67 7F 0C 8E A7 31 98 32 85 39
              :            40 9D 11 98 D8 DE B8 7F 86 9B AF 8D 67 3D B6 76
              :            B4 61 2F 21 E1 4B 0E 68 FF 53 3E 87 DD D8 71 56
              :            68 47 DC F7 20 63 4B 3C 5F 78 71 83 E6 70 9E E2
              :            92
   458 30   26:           SEQUENCE {
   460 03   21:             BIT STRING 0 unused bits
              :            1C D5 3A 0D 17 82 6D 0A 81 75 81 46 10 8E 3E DB
              :            09 E4 98 34
   483 02    1:             INTEGER 55
              :             }
              :           }
              :         }
   486 03  132:       BIT STRING 0 unused bits
              :         02 81 80 5F CF 39 AD 62 CF 49 8E D1 CE 66 E2 B1
              :         E6 A7 01 4D 05 C2 77 C8 92 52 42 A9 05 A4 DB E0
              :         46 79 50 A3 FC 99 3D 3D A6 9B A9 AD BC 62 1C 69
              :         B7 11 A1 C0 2A F1 85 28 F7 68 FE D6 8F 31 56 22
              :         4D 0A 11 6E 72 3A 02 AF 0E 27 AA F9 ED CE 05 EF



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Internet-Draft             DH POP Algorithms                  March 2013


              :         D8 59 92 C0 18 D7 69 6E BD 70 B6 21 D1 77 39 21
              :         E1 AF 7A 3A CF 20 0A B4 2C 69 5F CF 79 67 20 31
              :         4D F2 C6 ED 23 BF C4 BB 1E D1 71 40 2C 07 D6 F0
              :         8F C5 1A
              :       }
   621 A0    0:     [0]
              :     }
   623 30   12:   SEQUENCE {
   625 06    8:     OBJECT IDENTIFIER '1 3 6 1 5 5 7 6 4'
   635 05    0:     NULL
              :     }
   637 03   72:   BIT STRING 0 unused bits
              :     30 45 02 21 00 A1 B5 B4 90 01 34 6B A0 31 6A 73
              :     F5 7D F6 5C 14 43 52 D2 10 BF 86 58 87 F7 BC 6E
              :     5A 77 FF C3 4B 02 20 59 40 45 BC 6F 0D DC FF 9D
              :     55 40 1E C4 9E 51 3D 66 EF B2 FF 06 40 9A 39 68
              :     75 81 F7 EC 9E BE A1
              :   }


Authors' Addresses

   Jim Schaad
   Soaring Hawk Consulting

   Email: ietf@augustcellars.com


   Hemma Prafullchandra
   Hy-Trust




















Schaad & PrafullchandraExpires September 28, 2013              [Page 40]


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