Quasi-cyclic LDPC codes from difference families

Improving the Rao-Nam secret key cryptosystem using regular EDF-QC-LDPC codes

This paper proposes an efficient joint secret key encryption-channel coding cryptosystem, based on regular Extended Difference Family Quasi-Cyclic Low-Density Parity-Check codes. The key length of the proposed cryptosystem decreases up to 85 percent using a new efficient compression algorithm. Cryptanalytic methods show that the improved cryptosystem has a significant security advantage over Ra...

On the Grobner Basis of a Family of Quasi-Cyclic LDPC Codes

On the Usage of LDPC Codes in the McEliece Cryptosystem

In this paper, a new variant of the McEliece cryptosystem, based on Low-Density Parity-Check (LDPC) codes, is studied. Random-based techniques allow to design large families of LDPC codes with equivalent error correction capability; therefore, in principle, such codes can substitute Goppa codes, originally used by McEliece in his cryptosystem. Furthermore, Quasi-Cyclic (QC) LDPC codes can be ad...

Cyclic and Quasi-Cyclic LDPC Codes on Row and Column Constrained Parity-Check Matrices and Their Trapping Sets

This paper is concerned with construction and structural analysis of both cyclic and quasi-cyclic codes, particularly LDPC codes. It consists of three parts. The first part shows that a cyclic code given by a parity-check matrix in circulant form can be decomposed into descendant cyclic and quasi-cyclic codes of various lengths and rates. Some fundamental structural properties of these descenda...

Nonbinary Quasi-Cyclic LDPC Cycle Codes with Low-Density Systematic Quasi-Cyclic Generator Matrices

In this letter, we propose an appealing class of nonbinary quasi-cyclic low-density parity-check (QC-LDPC) cycle codes. The parity-check matrix is carefully designed such that the corresponding generator matrix has some nice properties: 1) systematic, 2) quasi-cyclic, and 3) sparse, which allows a parallel encoding with low complexity. Simulation results show that the performance of the propose...