On the Construction of Variable-Input-Length Ciphers

Whereas a block cipher enciphers messages of some one particular length the blocklength, a variable-input-length cipher takes messages of varying and preferably arbitrary lengths. Still, the length of the ciphertext must equal the length of the plaintext. This paper introduces the problem of constructing such objects, and provides a practical solution. Our VIL mode of operation makes a variable-input-length cipher from any block cipher. The method is demonstrably secure in the provable-security sense of modern cryptography: we give a quantitative security analysis relating the di culty of breaking the constructed variable-input-length cipher to the di culty of breaking the underlying block cipher.

• Type: Conference
• Year: 1999
• Where: FSE
• Authors: Mihir Bellare, Phillip Rogaway
• Keywords: Block Cipher, Block Cipher Enciphers, Cryptology, FSE 1999, Variable-input-length Cipher