Cryptanalysis of an Extension of the Hill Cipher. - Indivar Gupta; Jasbir Singh; Roopika Chaudhary (Cryptologia, 2007)

Relation for Algebraic Attack on E0 combiner. - N. Rajesh Pillai; S. S. Bedi; Sanjay Kumar; Roopika Chaudhary (IACR Cryptol. ePrint Arch., 2010)