The 3rd International CryptoForma workshop will be co-located with ESORICS 2013, at Royal Holloway University of London on 12 September 2013. The previous workshops targeted the Cryptology (Paris 2010) and Formal Methods (Limerick 2011) communities – this time we are holding a workshop looking at the formal verification of security protocols and cryptography at a major security conference. The workshop includes an invited talk from Steve Kremer, INRIA Nancy.