Tools for proofs

Security proof  for even simple cryptographic systems are dangerous and ugly beasts. Luckily, they are only rarely seen: they are usually safely kept in the confines of ``future full-versions'' of papers, or only appear in cartoon-ish form, generically labelled as ... ``proof sketch". The following two quotes frame the problem in less metaphorical terms. `` In our opinion, many proofs in cryptography have become essentially  unverifiable. Our field may be approaching a crisis of rigor ". Bellare