Is the Data Encryption Standard a Group? (Preliminary Abstract).

Burton S. Kaliski Jr. Ronald L. Rivest Alan T. Sherman Is the Data Encryption Standard a Group? (Preliminary Abstract). 81-95 http://link.springer.de/link/service/series/0558/bibs/0219/02190081.htm 1985 EUROCRYPT db/conf/eurocrypt/eurocrypt85.html#KaliskiRS85