Hot answers tagged mac
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One of the factors that determines how hard it is to forge a MAC for a given message is how long the MAC is. If it's 1 bit long, you can definitely produce the correct MAC in two tries.
$2^n$ is the number of possible bit-strings of length $n$; $1/2^n$ is the probability that any random bit-string happens to be the MAC (of length $n$) for a given message ...
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