The Security of Triple Encryption and a Framework for Code-Based Game-Playing Proofs

We show that, in the ideal-cipher model, triple encryption (the cascade of three independently-keyed blockciphers) is more secure than single or double encryption, thereby resolving a long-standing open problem. Our result demonstrates that for DES parameters (56-bit keys and 64-bit plaintexts) an adversary's maximal advantage against triple encryption is small until it asks about 278 queries. Our proof uses codebased game-playing in an integral way, and is facilitated by a framework for such proofs that we provide.

• Type: Conference
• Year: 2006
• Where: EUROCRYPT
• Authors: Mihir Bellare, Phillip Rogaway
• Keywords: Adversary's Maximal Advantage, Cryptology, EUROCRYPT 2006, Long-standing Open Problem, Triple Encryption