Contemporary Cryptology Provable Security for Public Key Schemes

摘要: Since the appearance of public-key cryptography in Die-Hellman seminal paper, many schemes have been proposed, but broken. Indeed, for a long time, simple fact that cryptographic algorithm had withstood cryptanalytic attacks several years was considered as kind validation. But some took time before being widely studied, and maybe thereafter A much more convincing line research has tried to provide \provable" security proto- cols, complexity theory sense: if one can break protocol, ecien tly solve underlying problem. Unfortunately, this initially purely theoretical work: very few practical could be proven so-called \standard model" because such level rarely meets with eciency . Ten ago, Bellare Rogaway proposed trade-o achieve validation t schemes, by identifying concrete objects ideal random ones. The most famous identication appeared \random-oracle model". More recently, another direction taken prove standard model (without any assumption) using stronger computational assumptions. In these lectures, we focus on asymmetric protocols together their \reductionist" proofs, mainly random-oracle model. We cover two main goals is devoted solve: authentication digital signatures, conden tiality encryption schemes.