Recognition of Channel Encoder Parameters from Intercepted Bitstream

We study recovering the channel encoder parameters for an unknown code from intercepted bitstream received from Binary Symmetric Channel in this paper. An iterativecolumn elimination algorithm is introduced which attempts to eliminate parity bits in codewords of noisy data. This algorithmis very practical due to low complexity and use of XOR operator. Since, the computational complexity is low, searching for the length of code and synchronization is possible. Furthermore, theHamming weight of the parity check words are only used in threshold computation and unlike other algorithms, they havenegligible effect in the proposed algorithm. Eventually, experimental results are presented and estimations for the maximumnoise level allowed for recovering the words of the parity check matrix are investigated