40-bit encryption

About: 40-bit encryption is a research topic. Over the lifetime, 5434 publications have been published within this topic receiving 149016 citations.

A computer useable product for generating data encryption/decryption apparatus

Abstract: One aspect of the invention provides a computer useable product co-operable with a circuit synthesis tool for generating a data encryption and apparatus for encrypting a block of plaintext data using a cipher key to produce a block of encrypted data. The product provides a first parameter, programmable by a user, the value of which determines the length of the cipher key. The product is arranged to cause the apparatus to implement a number of encryption rounds, the number of rounds depending on the value of the first parameter. The computer useable product further includes means for implementing a key schedule module for generating, from the cipher key, a number of round keys for use in respective encryption rounds, the number of generated round keys depending on the value of the first parameter. The product preferably takes the form of one or more blocks of HDL (Hardware Description Language) code.

A Method for Loading Encryption Keys Into Secure Transmission Devices

Abstract: An encryption code and at least one key are provided to a secure transmission device, via an external keying device (100) and stored in a first volatile memory (102). An encrypted representation of the at least one key, based on the encryption code and the at least one key, is generated and stored in a non-volatile memory (103). Upon power down of the secure transmission device, the encryption code is stored in a second volatile memory (106) and the at least one key and encryption code stored in the first volatile memory (102) are erased.

Selective Opening Security for Receivers

Abstract: In a selective opening SO attack an adversary breaks into a subset of honestly created ciphertexts and tries to learn information on the plaintexts of some untouched but potentially related ciphertexts. Contrary to intuition, standard security notions do not always imply security against this type of adversary, making SO security an important standalone goal. In this paper we study receiver security, where the attacker is allowed to obtain the decryption keys corresponding to some of the ciphertexts. First we study the relation between two existing security definitions, one based on simulation and the other based on indistinguishability, and show that the former is strictly stronger. We continue with feasibility results for both notions which we show can be achieved from variants of non-committing encryption schemes. In particular, we show that indistinguishability-based SO security can be achieved from a tweaked variant of non-committing encryption which, in turn, can be instantiated from a variety of basic, well-established, assumptions. We conclude our study by showing that SO security is however strictly weaker than all variants of non-committing encryption that we consider, leaving potentially more efficient constructions as an interesting open problem.

Improved cryptographically secure pseudo-random bit generator for fast and secure encryption

Abstract: The cryptographically secure pseudo-random bit generator (100) includes a front-end generator (102), a selector (104), a random function processor (106), a graph processor (108), and a bit-wise exclusive-or circuit (110). This cryptographically secure pseudo-random bit generator (100) stretches bit strings by the use of certain one-way functions acting on the bit strings. In addition, bit strings are generated from other input bit strings using expander graphs. The stretched bit strings and the bit strings from the expander graphs are combined in the bit-wise exclusive-or circuit.

Authenticated on-line encryption

Abstract: In this paper, we investigate the authenticated encryption paradigm, and its security against blockwise adaptive adversaries, mounting chosen ciphertext attacks on on-the-fly cryptographic devices. We remark that most of the existing solutions are insecure in this context, since they provide a decryption oracle for any ciphertext. We then propose a generic construction called Decrypt-Then-Mask, and prove its security in the blockwise adversarial model. The advantage of this proposal is to apply minimal changes to the encryption protocol. In fact, in our solution, only the decryption protocol is modified, while the encryption part is left unchanged. Finally, we propose an instantiation of this scheme, using the encrypted CBC-MAC algorithm, a secure pseudorandom number generator and the Delayed variant of the CBC encryption scheme.