The Twofish Encryption Algorithm

Since many people responded positively to the programming poll, here is a presentation of the TwoFish encryption algorithm, a possible DES-replacement which is unencombered by patents and for which a sample source code implementation is available. Basic Cryptography concepts are explained here and more simply here, while a look at unbalanced Feistel networks are also online. An alternative to TwoFish is Loki 97. Don't assume this article sets the tone for the series (it's rather hard) and the series will be varied. A substantial number of you wanted to be able to look only at news sections that interested you, and I think Rob is looking at implementing that.