منابع مشابه
Efficient Cryptanalysis of Homophonic Substitution Ciphers
Substitution ciphers are among the earliest methods of encryption. Examples of classic substitution ciphers include the well-known simple substitution and the less well-known homophonic substitution. Simple substitution ciphers are indeed simple, both in terms of their use and their cryptanalysis. Homophonic substitutions—in which a plaintext symbol can map to more than one ciphertext symbol—ar...
متن کاملAn Information-Theoretic Treatment of Homophonic Substitution
The history of cryptology shows that most secret-key cipher systems that have been broken were broken by exploiting the departure of the plaintext statistics from those of a completely random sequence. The technique of "homophonic substitution" is an old technique for converting an actual plaintext sequence into a (more) random sequence. At EUROCRYPT '88, Günther [1] introduced an important gen...
متن کاملEfficient Attacks on Homophonic Substitution Ciphers
Efficient Attacks On Homophonic Substitution Ciphers by Amrapali Dhavare Substitution ciphers are one of the earliest types of ciphers. Examples of classic substitution ciphers include the well-known simple substitution and the less well-known homophonic substitution. Although simple substitution ciphers are indeed simple both in terms of their use and attacks; the homophonic substitution ciphe...
متن کاملEfficient homophonic coding
Homophonic coding, or homophonic substitution, is referred to as a technique that contributes to reliability of the secret-key cipher systems. Its main goal is to convert the plaintext into a sequence of completely random (equiprobable and independent) code letters. In solving this problem three characteristics are to be considered: i) redundancy, defined as the difference between the mean code...
متن کاملEquivolcations for Homophonic Ciphers
Substitution ciphers can be quite weak when the probability distribution of the message letters is distinctly non-uniform. A timehonoured solution to remove this weakness is to "split" each high-pro bability letter into a number of "homophones" and use a substitution cipher for the resulting extended alphabet. Here the performance of a homophonic cipher is studied from a 'Shannon-theoretic poin...
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ژورنال
عنوان ژورنال: Anais da Academia Brasileira de Ciências
سال: 2002
ISSN: 1678-2690,0001-3765
DOI: 10.1590/s0001-37652002000300037