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

[Antonio Sanso]

hi Georgi,

On Sep 28, 2016, at 4:35 PM, Georgi Guninski <guninski at guninski.com> wrote:

> On Wed, Sep 28, 2016 at 12:27:31PM +0300, Georgi Guninski wrote:
>> Posting the keys/certs/private per some requests. The README:
>> 
>> Distinct DSA keys produce valid single signature of single file
>> and the x509 certificates from the private keys work on openssl 1.0.2j
>> 
>> Tested on openssl 1.0.2j (latest and 1.0.1t latest) on Debian 8.
>> 
>> The keys (also private are attached).
>> 
>> Also at http://j.ludost.net/DSA1.tar.gz
>> 
> 
> [this thread is crossposted to Cryptography and Cypherpunks]
> 
> Isn't there RFC or some document which says what checks should be
> made?
> 
> Last year I bitched:
> 
> RFC-2631, fips 186-3 and openssl's implementation of DSA appear broken (and possibly backdoored)
> 
> https://j.ludost.net/blog/archives/2015/09/05/rfc-2631_fips_186-3_and_openssls_implementation_of_dsa_appear_broken_and_possibly_backdoored/index.html
> https://lists.cpunks.org/pipermail/cypherpunks/2015-September/009007.html
> https://lists.cpunks.org/pipermail/cypherpunks/2015-September/024560.html
> #^ openssl

just saying. Have you seen this http://blog.intothesymmetry.com/2016/01/openssl-key-recovery-attack-on-dh-small.html ?


regards

antonio

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