Paper 2004/120

Security of Symmetric Encryption Schemes with One-Way IND-CNA Key Setup

Bartosz Zoltak

Abstract

We analyse the consequences of specific properties of the key-setup phase in symmetric encryption schemes for their security. We find that key-setup routines satisfying IND-CNA and one-wayness allow to construct schemes which are provably secure against key-recovery attacks. We propose a specific cryptosystem based on a stream cipher with a one-way IND-CNA key-setup, for which we present a proof, based on a set of scheme-specific assumptions, that it remains secure even if a successful key-recovery attack against the underlying cipher is found.

Note: The paper was shortened and made more concise