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[Python-Dev] PEP 427 comment: code signing

martin at v.loewis.de martin at v.loewis.de
Thu Oct 18 20:21:14 CEST 2012 
I'm -1 on the usage of ed25519 in PEP 427. While the PEP proposes to use JSON
Web signatures, this algorithm is not supported by the current JWS draft [1].

Instead, I suggest to use the ES256 algorithm from JWS, i.e. ECDSA with the
NIST P-256 curve and SHA-256. This has the advantage of using standard
algorithms [2].

I don't know what the rationale for suggesting ed25519 is; I suppose that
existence of a pure-Python implementation played a role. However:
- ECDSA also has a pure-Python implementation
- ECDSA is well-supported by OpenSSL, i.e. a signature generator may also
   invoke the OpenSSL command line for efficient implementation. I believe
   M2Crypto also exposes enough of OpenSSL tp perform ECDSA signing and
   verification.

I'm -0 on the use of JWS; I would prefer a signature format that is already
an established internet standard (such a PGP or S/MIME). However, it does look
that this may become a proper internet standard in the near future, so it's
an ok choice.

If it really must be ed25519, I request that this is registered with IANA
once the PEP is accepted, the RFC is accepted, and the JWS algorithm
registry is open.

Regards,
Martin

[1] http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-06
[2] http://tools.ietf.org/html/draft-ietf-jose-json-web-algorithms-06
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