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Re: public key algorithm naming

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At 04:03 PM 4/6/98 -0700, EKR wrote:
>fredette@theory.lcs.mit.edu (Matt Fredette) writes:
>> > Message-Id: <3.0.3.32.19980314020906.00a55100@cybercash.com>
>> In a conversation Carl and I had at IETF, he remarked that he had convinced
>> Eric Rescorla that the signature encoding algorithm does need to be part
>> of a key's name.  Here's the argument: if encoding algorithm could be 
>> specified on a signature-by-signature basis, I might construct a new, 
>> not-unreasonable encoding algorithm that, with certs of my choosing, lets
>> me reuse your RSA-PKCS1 signatures as signatures using my marvelous new
>> encoding.
>Matt, I'm having a really hard time reading your message to see
>what it is you currently believe. Is the above text a quote or
>your current position?
>
>In any case, I do NOT agree that the signature encoding algorithm
>needs to be part of a key's name. PKCS-1 itself prevents the
>substitution attack, as I believe I indicated at IETF.


Eric,

	Matt's wording was a little muddled here.  PKCS-1 *is* the encoding
algorithm he was talking about.

	What you and I agreed was that the PKCS-1 needs to be specified.  If all 
you specify is "rsa", then I have an unpacking algorithm that can pull the 
hash of my own construction out of an RSA-PKCS1 block.


[...]

>There's another quibble I have with all of this: PKCS-1 is both
>a message padding AND a format for RSA key encoding. But PKIX does
>NOT use the PKCS-1 RSA key encoding. Consequently, having a 
>key tagged as rsa-pkcs1 seems kind of confusing.

Are you suggesting we should write and name our own packing algorithm?

What does PKIX call its algorithm?

 - Carl

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