Maniphest T1583

Research ECDSA hash truncation
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• werner
Authored By
lumag
Dec 16 2013, 8:49 PM
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lumag
• werner

Description

Major crypto (TLS) library sources in ECDSA signature computation/verification
truncate hash value to the bitsize of the curve.
Research if adding such truncation will impact GnuPG or other users of libgcrypt.
Patch is proposed at
http://thread.gmane.org/gmane.comp.encryption.gpg.libgcrypt.devel/3401

Details

Version
1.6

Related Objects

Event Timeline

lumag added a subscriber: lumag.Dec 16 2013, 8:49 PM

D185: 412_0001-Truncate-hash-values-for-ECDSA-signature-scheme.patch

lumag set Version to 1.6.Dec 16 2013, 8:49 PM
lumag added projects: libgcrypt, Bug Report, patch.

References:

OpenSSL
http://git.openssl.org/gitweb/?
p=openssl.git;a=blob;f=crypto/ecdsa/ecs_ossl.c;h=adab1f74b41daf6e719ca1fdae1ba81
7085c7802;hb=HEAD#l309

Nettle:
http://git.lysator.liu.se/nettle/nettle/blobs/master/ecc-ecdsa-sign.c#line86
http://git.lysator.liu.se/nettle/nettle/blobs/master/ecc-hash.c

NSS:
https://hg.mozilla.org/projects/nss/file/49360b638350/lib/freebl/ec.c#l746

• werner added a subscriber: • werner.Jan 20 2014, 10:58 AM

This has meanwhile been fixed in master with commit 9edcf109.
I don't see a reason tobackport it to 1.6.

• werner closed this task as Resolved.Jan 24 2014, 10:52 AM
• werner claimed this task.

Oh well, backporting is easy enough. Commit id f6bd8ed, will go into 1.6.1.