Re: Compatibility between S/MIME v2 & v3 signatures

["Housley, Russ" <[e-mail]>]

Gwangsoo:

RFC 2315 only supports PKCS#1 v1.5 RSA signatures.  RFC 2630 and rfc2630bis 
support any signature algorithm.  So, the more correct backward 
compatibility statement is: RFC 2630 is backwards compatible with RFC 2315 
when PKCS#1 v1.5 RSA signatures are used.

Russ

At 10:08 AM 6/4/2002 +0900, Gwangsoo Rhee wrote:

>Hello, everybody.
>
>Many documents including draft-ietf-smime-rfc2630bis-08.txt
>claim that S/MIME v2 & v3 signatures are compatible, BUT:
>
>Sec. 9.4 of RFC 2315 (PKCS #7 v1.5) states about the signature
>generation:
>
>    The result of the
>    digest-encryption process is the encryption with the signer's private
>
>    key of the BER encoding of a value of type DigestInfo:
>
>    DigestInfo ::= SEQUENCE {
>      digestAlgorithm DigestAlgorithmIdentifier,
>      digest Digest }
>
>And sec. 5.5 of RFC 2630 (CMS) states:
>
>    The input to the signature generation process includes the result of
>    the message digest calculation process and the signer's private key.
>
>This RFC has no mention of DigestInfo structure.
>It seems to me that DigestAlgorithmIdentifier doesn't
>contribute to the signature generation, and in that case
>those two signatures cannot be compatible.
>
>Can anyone please point out where I got this wrong?
>
>Thanks.
>
>--
>
>---------------------------------------
>Gwangsoo Rhee <[e-mail]>
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>HP: 011-9691-9541
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