Background. The class on complexity goes through how to design a fixed block size motion estimator. It is useful to have reviewed that class before proceeding with this document. Basically, often in video the only difference between much of the content in subsequent frames is motion (imagine panning a camera slowly over a fixed scene). If this is true the difference between subsequent frames ca...

In this paper, we present One-key CBC MAC (OMAC) and prove its security for arbitrary length messages. OMAC takes only one key, K (k bits) of a block cipher E. Previously, XCBC requires three keys, (k + 2n) bits in total, and TMAC requires two keys, (k + n) bits in total, where n denotes the block length of E. The saving of the key length makes the security proof of OMAC substantially harder th...

LBlock is a lightweight block cipher proposed in ACNS 2011. It has 64-bit block size and 80-bit key size which is the typical parameter setting accpeted by most of the recent proposed lightweight block ciphers. It has fast hardware implementation efficiency and it still remains rather secure considering the recent results and the security margin it provides. In this paper, we investigate the di...

In cryptanalysis of block ciphers, there are several attacks that are always feasible and for which the success probability and complexity only depend on key length and/or block size. Exhaustive key search and table precomputation are two of such attacks. In Hel80] an attack was introduced which provides a tradeoo between the processing complexity of exhaustive key search and the memory complex...

We propose a new block cipher LEA, which has 128-bit block size and 128, 192, or 256-bit key size. It provides a high-speed software encryption on general-purpose processors. Our experiments show that LEA is faster than AES on Intel, AMD, ARM, and ColdFire platforms. LEA can be also implemented to have tiny code size. Its hardware implementation has a competitive throughput per area. It is secu...

MIBS is a 32-round lightweight block cipher with 64-bit block size and two different key sizes, namely 64-bit and 80-bit keys. Bay et al. provided the first impossible differential, differential and linear cryptanalyses of MIBS. Their best attack was a linear attack on the 18-round MIBS-80. In this paper, we significantly improve their attack by discovering more approximations and mounting Herm...