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Re: public key algorithm naming
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EKR <ekr@terisa.com> scrawled:
>
> 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.
>
I don't understand your point here. PKIX Part 1, section 7.2.1 (RSA
Signature Algorithm) clearly says to use PKCS1 -- the algorithm IDs it
specifies for RSA signatures are PKCS IDs. I'll admit that the same section
contains a description of a signature algorithm that is _not_ PKCS1, but I
suspect that's more an editing oversight than an intended deviation.
Anyway, for the record, I think it's better to just use rsa-pkcs1 and
dsa-sha1 (couldn't that just be "dss"?), but here's a little caveat: PKCS1
doesn't specifically talk about SHA1. In fact, for RSA-with-SHA1, PKIX uses
a non-PKCS algorithm ID (instead it's one from the OSI Interoperability
Workshop). There's no reason I can see that SHA1 can't be used in the PKCS1
style just like MD* are, and I'm 99.9% sure that's how its done in practice,
but it's not actually specified in PKCS1.
There may be more nuance here than can be captured by a simple identifier,
if we want to leave out hash algorithms.
Marc
+------------------------------------------------------------------------+
Marc Branchaud \/
Chief PKI Architect /\CERT INTERNATIONAL INC.
marcnarc@xcert.com PKI References page: www.xcert.com
604-640-6227 www.xcert.com/~marcnarc/PKI/
+------------------------------------------------------------------------+
PGP key fingerprint: 60 11 4B 9D 4E E5 2F 47 BD C5 C2 BF 26 DF 5A E1
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