[PYTHON-CRYPTO] DSA signature verification trouble...

[Dan Berger]

Doh!

Never mind - the arguments were reversed.

Don't I feel silly.

On Wed, 2004-08-04 at 11:19 -0700, Dan Berger wrote:
> I thought this was a problem between my Python and C code, but it looks
> like either there's a problem in M2Crypto (possibly OpenSSL), or I'm
> missing something.  Consider the following code:
> 
> import M2Crypto
> import M2Crypto.DSA
> import M2Crypto.EVP
> ksk = M2Crypto.DSA.load_key("/home/dberger/Projects/IKaRoS/server/db/ksk_1.pem")
> signature = ksk.sign_asn1("foobar")
> ksk.verify_asn1(signature, "foobar")
> 
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "/usr/lib/python2.2/site-packages/M2Crypto/DSA.py", line 132, in verify_asn1
> M2Crypto.DSA.DSAError: too long
> 
> Feeding a signature produced by sign_asn1 directly into verify_asn1
> fails.  Anyone have any suggestions?
> 
> By the way - doing this:
> 
> import M2Crypto
> import M2Crypto.DSA
> import M2Crypto.EVP
> ksk = M2Crypto.DSA.load_key("/home/dberger/Projects/IKaRoS/server/db/ksk_1.pem")
> signature = ksk.sign("foobar")
> ksk.verify("foobar", signature[0], signature[1])
> 
> returns success, which suggests it's a problem with the asn1 encode/decode "stuff."
> 
> --
> 
> ...Dan Berger [dberger at cs.ucr.edu]
>    Department of Computer Science
>    Surge Building, Room 357
>    University of California, Riverside
>    http://www.cs.ucr.edu/~dberger
> 
>    "I like naked women. I'm a bloke. I'm supposed to like them. We're
>     born like that. We like naked women as soon as we're pulled out of
>     one. Halfway down the birth canal we're already enjoying the view!"
> 
>                         - Steve, Coupling: "Inferno"
--

...Dan Berger [dberger at cs.ucr.edu]
   Department of Computer Science
   Surge Building, Room 357
   University of California, Riverside
   http://www.cs.ucr.edu/~dberger

   "No boom?"
   "No boom."
   "No boom *today*. Boom tomorrow. There's *always* a boom tomorrow."
   "What?"
   "Look, somebody's got to have some damn perspective around here.
    Boom, sooner or later. *BOOM*!"

               - Garibaldi, Sinclair, and Ivanova, Babylon 5: "Grail"
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