In this paper, we cryptanalyze LEX using two related keys. We have mounted a key recovery attack on LEX, which using $2^{54. 3}$ key streams yields a complete round key with $2^{102}$ operations. This improves the existing best cryptanalysis of LEX which needs $2^{112}$ operations to ascertain the key.
Category / Keywords: secret-key cryptography / Date: received 10 Jan 2010, withdrawn 19 Apr 2010 Contact author: mainack mondal at gmail com Available formats: (-- withdrawn --) Note: We are withdrawing this paper due to technical errors in it. Please remove it from the achive. Version: 20100419:061248 (All versions of this report) Discussion forum: Show discussion | Start new discussion