CONSTRUCTION AND USES OF VARIABLE-INPUT-LENGTH TWEAKABLE CIPHERS

摘要

Innovations in the construction and use of variable-input-length tweakable ciphers ("VILTCs"). In some cases, a VILTC uses an initialization vector that is protected from exposure outside an encryption/decryption system in order to provide enhanced security with efficient performance. For example, a system for encryption and/or decryption includes two fixed-input-length tweakable block ciphers ("FIL TBCs") and a VILTC. The first FIL TBC is adapted to produce a fixed-length initialization vector. The VILTC is adapted to produce a variable-length output string using the fixed-length initialization vector as a tweak. The second FIL TBC is adapted to produce a fixed-length output string. In this way, the first FIL TBC and the second FIL TBC protect the fixed-length initialization vector from exposure outside the system. In other cases, a VILTC is used for a reliable and efficient implementation of authenticated encryption/decryption with associated data.