Support for Anonymous Diffie-Hellman

Dear S/MIME WG:

> From the discussion on the list, I am convinced that there is concensus for
support of anonymous Diffie-Hellman.  I proose the following syntax for this
support.

I prefer this syntax to others that have been proposed on the list because
irequires a certificate identifier or a public key, and it does not permit
someone to make a mistake by omitting both.

Russ

= = = = = = = = = = 


KeyAgreeRecipientInfo ::= SEQUENCE {
  version Version,  -- always set to 3
  originator [0] EXPLICIT OriginatorIdentifierOrKey,
  ukm [1] EXPLICIT UserKeyingMaterial OPTIONAL,
  keyEncryptionAlgorithm KeyEncryptionAlgorithmIdentifier,
  recipientEncryptedKeys RecipientEncryptedKeys }

OriginatorIdentifierOrKey ::= CHOICE {
  issuerAndSerialNumber IssuerAndSerialNumber,
  subjectKeyIdentifier [0] SubjectKeyIdentifier,
  originatorKey [1] OriginatorPublicKey }

OriginatorPublicKey ::= SEQUENCE {
  algorithm AlgorithmIdentifier,
  publicKey BIT STRING }

RecipientEncryptedKeys ::= SEQUENCE OF RecipientEncryptedKey

RecipientEncryptedKey ::= SEQUENCE {
  rid RecipientIdentifier,
  encryptedKey EncryptedKey }

RecipientIdentifier ::= CHOICE {
  issuerAndSerialNumber IssuerAndSerialNumber,
  rKeyId [0] IMPLICIT RecipientKeyIdentifier }

RecipientKeyIdentifier ::= SEQUENCE {
  subjectKeyIdentifier SubjectKeyIdentifier,
  date GeneralizedTime OPTIONAL,
  other OtherKeyAttribute OPTIONAL }

SubjectKeyIdentifier ::= OCTET STRING