In
cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adve ...
, decorrelation theory is a system developed by
Serge Vaudenay in 1998 for designing
block cipher
In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called ''blocks''. Block ciphers are specified cryptographic primitive, elementary components in the design of many cryptographic protocols and ...
s to be
provably secure
Provable security refers to any type or level of computer security that can be proved. It is used in different ways by different fields.
Usually, this refers to mathematical proofs, which are common in cryptography. In such a proof, the capabiliti ...
against
differential cryptanalysis,
linear cryptanalysis
In cryptography, linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers. Linear cryptanalysis is one of the two ...
, and even undiscovered cryptanalytic attacks meeting certain broad criteria. Ciphers designed using these principles include
COCONUT98
In cryptography, COCONUT98 (Cipher Organized with Cute Operations and N-Universal Transformation) is a block cipher designed by Serge Vaudenay in 1998. It was one of the first concrete applications of Vaudenay's decorrelation theory, designed to ...
and the
AES candidate DFC, both of which have been shown to be vulnerable to some forms of
cryptanalysis not covered by the theory.
According to Vaudenay, the decorrelation theory has four tasks: 1) the definition of a measurement for the decorrelation, which usually relies on a matrix norm; 2) the construction of simple primitive or "decorrelation module" with a quite good decorrelation; 3) the construction of
cryptographic algorithms
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adver ...
with decorrelation modules so that the primitive can be inherited by the algorithm; and, 4) proving that the decorrelation provides security against attacks.
[Serve Vaudenay (May 2003). "Adaptive-Attack Norm for Decorrelation and Super-Pseudorandomness," In Howard Heys and Carlisle Adams' Selected Areas in Cryptography: 6th Annual International Workshop, SAC'99 Kingston, Ontario, Canada, August 9-10, 1999 Proceedings. Berlin: Springer. pp. 49-61. ]
References
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External links
Introduction to Decorrelation TheoryOnline manual by Serge Vaudenay
Theory of cryptography
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