Integrity-Aware Mode of Stream Cipher


IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.1   pp.58-65
Publication Date: 2002/01/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Cryptography and Information Security)
stream cipher,  modes of operation,  perfect secrecy,  message authenticity,  

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In many cryptographic protocols, a common-key encryption is used to provide a secure data-transmission channel. More precisely, the general idea of protocols is to have an encryption provide data authenticity as well as data confidentiality. In fact, there are known to be quite a few ways to provide both forms of security, however none of them are optimized enough to be efficient. We present a new encryption mode that uses a random number generator (RNG). Assuming the security of the RNG, we can prove not only perfect secrecy, but also message authentication. The proven probability of a successful forgery is (n-1)/(2b-1), where b is the number of bits in a block and n is the number of ciphertext blocks. The proposed scheme achieves very high practicality due to the potential advantages in efficiency. When we use a computationally secure RNG, such as instance a pseudorandom number generator PRNG, we have advantages in efficiency; in addition to the PRNG parallel computation, the scheme requires only a single-path process on the data stream so that even a limited hardware resource can operate an encryption of a very long data stream. We demonstrate the practicality of our scheme, by showing a realistic parameter set and the evaluations of its performance.