Like DES, LOKI97 is a 16-round Feistel cipher, and like other AES candidates, has a 128-bit block size and a choice of a 128-, 192- or 256-bit key length.

The authors have stated that, "LOKI97 is a non-proprietary algorithm, available for royalty-free use worldwide as a possible replacement for the DES or other existing block ciphers."

It was the first published candidate in the Advanced Encryption Standard competition, and was quickly analysed and attacked.

An analysis of some problems with the LOKI97 design, which led to its rejection when shortlisting candidates, is given in a paper (Rijmen & Knudsen 1999).

It was found to be susceptible to an effective theoretical differential cryptanalysis attack considerably faster than an exhaustive search.