A New Mode of Encryption Providing a Tweakable Strong Pseudo-random Permutation

We present PEP, which is a new construction of a tweakable strong pseudo-random permutation. PEP uses a hash-encrypt-hash approach which has recently been used in the construction of HCTR. This approach is different from the encrypt-mask-encrypt approach of constructions such as CMC, EME and EME . The general hash-encrypt-hash approach was earlier used by Naor-Reingold to provide a generic construction technique for an SPRP (but not a tweakable SPRP). PEP can be seen as the development of the Naor-Reingold approach into a fully specified mode of operation with a concrete security reduction for a tweakable strong pseudo-random permutation. The security bound of HCTR which is also based on the Naor-Reingold approach is weaker than that of PEP. Compared to previous known constructions, PEP is the only construction of tweakable SPRP which uses a single key, is efficiently parallelizable and can handle an arbitrary number of blocks.

• Type: Conference
• Year: 2006
• Where: FSE
• Authors: Debrup Chakraborty, Palash Sarkar
• Keywords: Cryptology, FSE 2006, Hash-encrypt-hash Approach, Naor-Reingold Approach, Strong Pseudo-random Permutation