Re: [TLS] Two notes on TLS 1.2 after implementing it in GnuTLS

[Mike <mike-list at pobox.com>]

> Further, appendix H of PKCS1B contains additional discussions:
>
>    *  The requirement that the parameters in an AlgorithmIdentifier
>       value for id-sha1, id-sha256, id-sha384, and id-sha512 be NULL was
>       changed to a recommendation that the parameters be omitted (while
>       still allowing the parameters to be NULL). This is to align with
>       the definitions originally promulgated by NIST. Implementations
>       MUST accept AlgorithmIdentifier values both without parameters and
>       with NULL parameters.
>
> I note that Mike's server required a NULL here.  I initially didn't
> send one, my ASN.1 library computed a DER encoding with an omitted
> parameters field.  For reference, that DER code is:
>
>   SHA-1: 30 1f 30 07 06 05 2b 0e 03 02 1a 04 14 || H
>
> Mike's server didn't accept this.
>
> This will leads to interoperability problems with TLS 1.2 unless the
> specification is more explicit about the problem.

I have to admit I don't understand this issue.  That's because I
didn't write any RSA code myself.  I used to use OpenSSL for SSL/TLS,
but was never sure if my code was correct, so I decided to write my
own implementation.  However, I am comfortable with the functions in
OpenSSL's libcrypto, so I used that for all public-key algorithms and
bulk encryption.

Perhaps I need to write my own RSA code instead of relying on OpenSSL
EVP functions for signing/verifying?

Mike

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