Perfect message authentication codes are robust to small deviations from uniform key distributions

Boris Ryabko

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arXiv · 2508.09783

Perfect message authentication codes are robust to small deviations from uniform key distributions

Boris Ryabko

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Abstract

We investigate the impact of (possible) deviations of the probability distribution of key values from a uniform distribution for the information-theoretic strong, or perfect, message authentication code. We found a simple expression for the decrease in security as a function of the statistical distance between the real key probability distribution and the uniform one. In a sense, a perfect message authentication code is robust to small deviations from a uniform key distribution.

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Boris Ryabko. 2025-08-13. Perfect message authentication codes are robust to small deviations from uniform key distributions. https://arxiv.org/abs/2508.09783

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