Showing papers on "Null cipher published in 1997"
Patent•
IBM1
TL;DR: In this article, a block encryption algorithm was proposed to encrypt a plaintext block using a block size smaller than that of the original plaintext blocks, and a ciphertext block was generated from the encrypted portion of the masked plaintext and the remaining portion.
Abstract: A system for encrypting a plaintext block using a block encryption algorithm having a block size smaller than that of the plaintext block. The plaintext block is transformed into a masked plaintext block using an invertible transformation optionally dependent on additional data and defined such that each bit of the masked plaintext block depends on every bit of the original plaintext block. A subportion of the masked plaintext block is encrypted using the encryption algorithm to generate an encrypted portion of the masked plaintext block. A ciphertext block is generated from the thus encrypted portion of the masked plaintext block and the remaining portion of the masked plaintext block. The ciphertext block is transmitted to a data recipient, who reverses the procedure to recover the original plaintext block. Since the entire masked plaintext block is necessary to reconstruct the original plaintext block and since the encrypted portion cannot be derived from the remaining portion, the remaining portion of the masked plaintext block may be transmitted to the recipient in unencrypted form. Two, three or four masking rounds are performed, depending on the location of secret data that is infeasible to exhaust and the location of the portion of the masked block that is encrypted.
69 citations
[...]
TL;DR: SPEED is a private key block cipher that supports three variable parameters: data length, key length and rounds.
Abstract: SPEED is a private key block cipher. It supports three variable parameters: (1) data length — the length of a plaintext/ciphertext of SPEED can be 64, 128 or 256 bits. (2) key length — the length of an encryption/decryption key of SPEED can be any integer between 48 and 256 (inclusive) and divisible by 16. (3) rounds — the number of rounds involved in encryption/decryption can be any integer divisible by 4 but not smaller than 32.
22 citations
Patent•
IBM1
TL;DR: In this paper, an elliptic curve algorithm with a block size on the order of 160 bits was used to encrypt a 512-bit plaintext block containing a symmetric encryption key.
Abstract: A system for encrypting a plaintext block using a block encryption algorithm having a block size smaller than that of the plaintext block. The plaintext block is transformed into a masked plaintext block using an invertible transformation optionally dependent on additional data and defined such that each bit of the masked plaintext block depends on every bit of the original plaintext block. A subportion of the masked plaintext block is encrypted using the encryption algorithm to generate an encrypted portion of the masked plaintext block. A ciphertext block is generated from the thus encrypted portion of the masked plaintext block and the remaining portion of the masked plaintext block. The ciphertext block is transmitted to a data recipient, who reverses the procedure to recover the original plaintext block. Since the entire masked plaintext block is necessary to reconstruct the original plaintext block and since the encrypted portion cannot be derived from the remaining portion, the remaining portion of the masked plaintext block may be transmitted to the recipient in unencrypted form. To thwart certain cryptanalytic attacks, either the plaintext block or the optional additional data is uniquely modified for each encryption of a plaintext block, using an incrementing counter, time stamp, random number or other mechanism. In an exemplary embodiment, an elliptic curve algorithm having a block size on the order of 160 bits is used to encrypt a 512-bit block containing a symmetric encryption key.
6 citations