# zbMATH — the first resource for mathematics

An efficient state recovery attack on X-FCSR-256. (English) Zbl 1248.94096
Dunkelman, Orr (ed.), Fast software encryption. 16th international workshop, FSE 2009, Leuven, Belgium, February 22–25, 2009. Revised selected papers. Berlin: Springer (ISBN 978-3-642-03316-2/pbk). Lecture Notes in Computer Science 5665, 23-37 (2009).
Summary: We describe a state recovery attack on the X-FCSR-256 stream cipher of total complexity at most $$2^{57.6}$$. This complexity is achievable by requiring $$2^{49.3}$$ output blocks with an amortized calculation effort of at most $$2^{8.3}$$ table lookups per output block using no more than $$2^{33}$$ table entries of precomputational storage.
For the entire collection see [Zbl 1168.68003].

##### MSC:
 94A60 Cryptography 94A55 Shift register sequences and sequences over finite alphabets in information and communication theory
##### Keywords:
stream cipher; FCSR; X-FCSR; cryptanalysis; state recovery
X-FCSR
Full Text: