Abstract
In 1997, M. Matsui proposed secret-key cryptosystems called MISTY 1 and MISTY 2, which are 8-and 12-round block ciphers with a 64-bit block, and a 128-bit key. They are designed based on the principle of provable security against differential and linear cryptanalysis. In this paper we present large collections of weak-key classes encompassing 273 and 270 weak keys for 7-round MISTY 1 and 2 for which they are vulnerable to a related-key amplified boomerang attack. Under our weak-key assumptions, the related-key amplified boomerang attack can be applied to 7-round MISTY 1 and 2 with 254, 256 chosen plaintexts and 255.3 7-round MISTY 1 encryptions, 265 7-round MISTY 2 encryptions, respectively.
| Original language | English |
|---|---|
| Pages (from-to) | 642-649 |
| Number of pages | 8 |
| Journal | IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences |
| Volume | E91-A |
| Issue number | 2 |
| DOIs | |
| State | Published - 2008 |
Keywords
- Block ciphers
- MISTY 1
- MISTY 2
- Related-key amplified boomerang attack
- Weak-key classes