For Full-Text PDF, please login, if you are a member of IEICE,|
or go to Pay Per View on menu list, if you are a nonmember of IEICE.
The Security of an RDES Cryptosystem against Linear Cryptanalysis
Yasushi NAKAO Toshinobu KANEKO Kenji KOYAMA Routo TERADA
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1996/01/25
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Cryptography and Information Security)
linear cryptanalysis, secret key cryptosystem, DES, probabilistic swapping, best expression,
Full Text: PDF(593.9KB)>>
RDES cryptosystem is an n-round DES in which an probabilistic swapping is added onto the right half of the input in each round. It is more effective than a simple increase of DES rounds for a countermeasure against differential attack. In this paper, we show that the RDES is also effective against linear cryptanalysis. We applied Matsui's search algorithm to find the best expression for RDES-1 and RDES-2. The results are as follows: (a) The 16-round RDES-1 is approximately as strong as a 22-round DES, and the 16-round RDES-2 is approximately as strong as a 29-round DES. (b) Linear cryptanalysis for a 16-round RDES-1 and a 16-round RDES-2 requires more than 264 known-plaintexts.