[tahoe-dev] [pycryptopp] #20: deterministic randomness in signing function

[pycryptopp]

#20: deterministic randomness in signing function
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Reporter:  zooko        |           Owner:       
    Type:  enhancement  |          Status:  new  
Priority:  major        |         Version:  0.5.1
Keywords:               |   Launchpad_bug:       
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 ECDSA is a randomized signing algorithm, which means there is an implicit
 RNG argument along with the key and message arguments to the sign
 operation.  Currently that RNG parameter is not in the API, but is
 provided implicitly at the Crypto++ layer.  To fix this ticket, add an
 optional "rng" parameter to the {{{.sign()}}} method.  The default value
 (i.e. not specifying any "rng" argument) has the current behavior -- use
 the default RNG provided by Crypto++.  The other alternative is to specify
 a random seed (a string of bytes of the right size) which will be used as
 the determiner of the random bits used in the ECDSA signature computation.

 I prefer the explicit approach, when it isn't too inconvenient, because it
 allows for reproducible behavior, such as testing digital signatures
 against fixed test vectors or reproducing and analyzing data-dependent
 bugs, and because it makes all the security requirements explicit.  (The
 security of your digital signatures relies not only on the security of the
 key but also on the (implicit) RNG.)

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Ticket URL: <http://allmydata.org/trac/pycryptopp/ticket/20>
pycryptopp <http://allmydata.org/trac/pycryptopp>
Python bindings for the Crypto++ library