The RFC 5114 saga

Back in January I posed a question "to the Internet": What the heck is RFC 5114? It looks like a lot happened since then around it. I would like to use this post to recollect some of the stuff around RFC5114 . Chapter 0: October 2007 RFC5114 draft was submitted to the IETF . Chapter I: January 20...

OpenSSL Key Recovery Attack on DH small subgroups (CVE-2016-0701)

Usual Mandatory Disclaimer: IANAC I am not a cryptographer so I might likely end up writing a bunch of mistakes in this blog post... tl;dr The OpenSSL 1.0.2 releases suffer from a Key Recovery Attack on DH small subgroups. This issue got assigned CVE-2016-0701 with a severity of High and OpenSSL...

Internet Bug Bounty: OpenSSL Key Recovery Attack on DH small subgroups (CVE-2016-0701)

Full write up: http://intothesymmetry.blogspot.ch/2016/01/openssl-key-recovery-attack-on-dh-small.html DH small subgroups CVE-2016-0701 ================================== Severity: High Historically OpenSSL usually only ever generated DH parameters based on "safe" primes. More recently in version...

Vulnerability in OpenSSL - DH small subgroups

Historically OpenSSL usually only ever generated DH parameters based on “safe” primes. More recently in version 1.0.2 support was provided for generating X9.42 style parameter files such as those required for RFC 5114 support. The primes used in such files may not be “safe”. Where an application ...

What the heck is RFC 5114?

Mandatory Disclaimer: IANAC I am not a cryptographer so I might likely end up writing a bunch of mistakes in this blog post... I already talked about Diffie–Hellman DH from now on in TLS in my previous post: Small subgroup attack in Mozilla NSS. As mentioned FWIW I strongly agree with Google Chro...