[Cryptography] Posting the keys/certs for: Two distinct DSA keys sign a file with the same signature. Is this repudiation issue?

[John Denker]

On 10/01/2016 05:29 AM, Georgi Guninski wrote:
> I see, openssl tries to generate valid stuff, while accepting invalid
> stuff by _bad_ "external programs".

The important thing is the notion of /repudiation/ as hypothesized
in the Subject: line.  Repudiation does not happen in a vacuum.

Consider what happens when you try to repudiate a document that has
been signed in a way that matches your public key.  You try to claim
that some bad guy forged your signature without using your private
key, using some "other" private key instead.  Everybody else says
no, you are the bad guy.  Your choice of keys proves you are the bad
guy.  In other words, the attempted repudiation is self-defeating,
at no cost to the other party.

  In contrast, good guys use valid keypairs.

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Openssl generates valid keypairs, as far as we can tell, so there
is no openssl issue here.  Overall, this discussion is sound and
fury, signifying nothing.

  In contrast, if there were a way for innocent parties to accidentally
  generate invalid keypairs, that would would be worth discussing.