Introducing the new LOKI97 Block Cipher
Lawrie Brown, Josef Pieprzyk · 1998
This paper describes LOKI97, a new private key block cipher with 128-bit data and a 256-bit key schedule, which can be initialised by 128, 192, or 256-bit keys. The data computation uses 16 rounds of a balanced Feistel network with a complex function f which incorporates two S-P layers. The 256-bit key schedule uses 48 rounds of an unbalanced Feistel network using the same complex function f to generate the subkeys. The cipher specification is given, followed by some background and design considerations, and a preliminary analysis. 1 Introduction LOKI97 is a new 16 round Feistel cipher on 128-bit data using a complex non-linear function f, with a 256-bit key schedule which can be initialised using 128, 192, or 256-bit keys. It has evolved from the earlier LOKI89 [BPS90], and LOKI91 [BKPS91] 64-bit block ciphers, with a strengthened key schedule, and a larger keyspace. The overall structure design and analysis of LOKI97 was performed by Dr Lawrie Brown during his 1997 sabbatical 1 , ...