Computationally indistinguishable
Encyclopedia
In computational complexity
, if
and 
are two distribution ensembles indexed by a security parameter
n (which usually refers to the length of the input), then we say they are computationally indistinguishable if for any non-uniform probabilistic polynomial time algorithm
A, the following quantity is a negligible function in n:
In other words, for every efficient algorithm A, its behavior does not significantly change when given samples according to Dn or En.
Computational Complexity
Computational Complexity may refer to:*Computational complexity theory*Computational Complexity...
, if
and are two distribution ensembles indexed by a security parameterSecurity parameter
In cryptography, the security parameter is a variable that measures the input size of the problem. Both the resource requirements of the cryptographic algorithm or protocol as well as the adversary's probability of breaking security are expressed in terms of the security parameter.The security...
n (which usually refers to the length of the input), then we say they are computationally indistinguishable if for any non-uniform probabilistic polynomial time algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
A, the following quantity is a negligible function in n:
In other words, for every efficient algorithm A, its behavior does not significantly change when given samples according to Dn or En.