Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A provably secure multi-server threshold password-authenticated key exchange system and method. Initially, an encryption of a function of a client's password is provided to each of a plurality of servers. The client later can authenticate the password (i.e., login) by generating an encryption based on the password which is nonetheless mathematically independent of the value of the password. Then, this encryption, along with a “proof” that the encryption was, in fact, generated based on the password, is provided to each of the servers for verification. Thus, it can be shown that the protocol is provably secure. The password authentication protocol advantageously incorporates a thresholding scheme such that the compromise of fewer than a given threshold number of the servers neither compromises the security of the system nor inhibits the proper operation of the password authentication process.