CAST-128

CAST is a symmetric block cipher with 64-bit block length and a key length of 40 to 128 bits. Alternative names are CAST -128 or CAST5. The CAST algorithm is named after its developers, Carlisle Adams and Stafford Tavares and 1996 applied for a patent. CAST can be used royalty-free in both commercial and non -commercial applications worldwide. Because of its higher speed compared to THE CAST is also suitable for real-time applications.

The successor CAST -256 was a candidate in the AES Challenge.

CAST until today has not been broken, so it is also included in many applications, such as PGP.

CAST is a Feistelchiffre. In each round, a data word is associated with a keyword (depending on the round by addition, subtraction or XOR ) and key -dependent rotated. It is divided into four sections of 8 bits each, which are substituted in each case a 8x32 bit S-box. Their outputs are related by the operations of addition, subtraction, and XOR. Their order is rotated from round to round. With the result, finally, the other data word (the second half of the block ) modified by XOR.

Swell

• C. M. Adams, " Constructing Symmetric Ciphers Using the CAST Design Procedure", 1997, Designs, Codes, and Cryptography, 12 (3 ), pp. 283-316. (English )