A theoretical analysis of the error correction capability of LDPC and MDPC codes under parallel bit-flipping decoding
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Iterative decoders used for decoding low-density parity-check (LDPC) and moderate-density parity-check (MDPC) codes are not characterized by a deterministic decoding radius and their error rate performance is usually assessed through intensive Monte Carlo simulations. However, several applications like code-based cryptography need guaranteed low values of the error rate, which are infeasible to assess through simulations, thus requiring the development of theoretical models for the error rate of these codes under iterative decoding. Some models of this type already exist, but become computationally intractable for parameters of practical interest. Other approaches attempt at approximating the code ensemble behaviour through assumptions, which however are hardly verified by a specific code and can barely be tested for very low error rate values. In this paper we propose a theoretical analysis of the error correction capability of LDPC and MDPC codes under a single-iteration parallel bit-flipping decoder that does not require any assumption. This allows us to derive a theoretical bound on the error rate of such a decoding algorithm, which hence results in a guaranteed error correction capability for any single code. We show an example of application of the new bound to the context of code-based cryptography, where guaranteed error rates are needed to achieve some strong security notions.
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