## Cryptology ePrint Archive: Report 2009/201

Enhanced Cryptanalysis of Substitution Cipher Chaining mode (SCC-128)

Mohamed Abo El-Fotouh and Klaus Diepold

Abstract: In this paper, we present an enhanced cryptanalysis of the Substitution Cipher Chaining mode (SCC)~\cite{scc}. In~\cite{scc_attack}, SCC-128 (SCC which uses AES with 128-bit key) was broken using 5 attacks, where the authors used an active attack model (where the attacker can force the disk encryption application to re-encrypt a sector for her), the complexity of these attacks are at most 2$^{40}$ cipher executions. In this paper, we enhance the main attack on SCC-128, this enhancement decrease the complexity of SCC-128 attacks to be at most 2$^{14}$ cipher executions. We also cryptanalze SCC-128 in a less restrictive attack model, our attacks are upper bounded with 2$^{40}$ cipher executions.

Category / Keywords: secret-key cryptography / cryptanalysis, SCC mode, disk encryption