×

Differential cryptanalysis and linear distinguisher of full-round zorro. (English) Zbl 1353.94077

Boureanu, Ioana (ed.) et al., Applied cryptography and network security. 12th international conference, ACNS 2014, Lausanne, Switzerland, June 10–13, 2014. Proceedings. Berlin: Springer (ISBN 978-3-319-07535-8/pbk). Lecture Notes in Computer Science 8479, 308-323 (2014).
Summary: Zorro is an AES-like lightweight block cipher proposed in CHES 2013, which only uses 4 S-boxes per round. The designers showed the resistance of the cipher against various attacks and concluded the cipher has a large security margin. Recently, J. Guo et. al [Cryptanalysis of Zorro. Cryptology ePrint Archive, Report 2013/713 (2013)] have given a key recovery attack on full-round Zorro by using the internal differential characteristics. However, the attack only works for \(2^{64}\) out of \(2^{128}\) keys. In this paper, the secret key selected randomly from the whole key space can be recovered much faster than the brute-force attack. We first observe that the fourth power of the MDS matrix used in Zorro (or AES) equals to the identity matrix. Moveover, several iterated differential characteristics and iterated linear trails are found due to the interesting property. We select three characteristics with the largest probability to give the key recovery attack on Zorro and a linear trail with the largest correlation to show a linear distinguishing attack with \(2^{105.3}\) known plaintexts. The results show that the security of Zorro against linear and differential cryptanalysis evaluated by designers is insufficient and the security margin of Zorro is not enough.
For the entire collection see [Zbl 1291.94001].

MSC:

94A60 Cryptography

Software:

Piccolo
PDFBibTeX XMLCite
Full Text: DOI