An Improved McEliece Cryptosystem Based on QC-LDPC Codes

In the original McEliece cryptosystem based on QC-LDPC codes, the decoding algorithm uses BF algorithm instead of BP algorithm, which reduces the time complexity but decreases the decoding performance. To solve this problem, we improve the original algorithm and use the Q-decoder which utilizes the correlation between the error pattern e and the matrix Q, making decoding performance much better. Finally, we analyze the security of the improved cryptosystem, finding it has a higher security level.