Biblio

With the increase of computing power of quantum computers, classical cryptography schemes such as RSA and ECC are no longer secure in the era of quantum computers. The Cryptosystem based on coding has the advantage of resisting quantum computing and has a good application prospect in the future. McEliece Public Key Cryptography is a cryptosystem based on coding theory, whose security can be reduced to the decoding problem of general linear codes and can resist quantum attacks. Therefore, this paper proposes a cryptosystem based on the Polar-LDPC Concatenated Codes, which is an improvement on the original McEliece cipher scheme. The main idea is to take the generation matrix of Polar code and LDPC code as the private key, and the product of their hidden generation matrix as the public key. The plain text is encoded by Polar code and LDPC code in turn to obtain the encrypted ciphertext. The decryption process is the corresponding decoding process. Then, the experimental data presented in this paper prove that the proposed scheme can reduce key size and improve security compared with the original McEliece cryptosystem under the condition of selecting appropriate parameters. Moreover, compared with the improvement schemes based on McEliece proposed in recent years, the proposed scheme also has great security advantages.

To achieve a fine-grained access control function and guarantee the data confidentiality in the cloud storage environment, ciphertext policy attribute-based encryption (CP-ABE) has been widely implemented. However, due to the high computation and communication overhead, the nature of CP-ABE mechanism makes it difficult to be adopted in resource constrained terminals. Furthermore, the way of realizing varying levels of undo operations remains a problem. To this end, the access matrix that satisfies linear secret sharing scheme (LSSS) was optimized with Cauchy matrix, and then a user-level revocation scheme based on Chinese Remainder Theorem was proposed. Additionally, the attribute level revocation scheme which is based on the method of key encrypt key (KEK) and can help to reduce the storage overhead has also been improved.

In this paper, a novel secure information exchange scheme has been proposed for MIMO vehicular ad hoc networks (VANETs) through physical layer approach. In the scheme, a group of On Board Units (OBUs) exchange information with help of one Road Side Unit (RSU). By utilizing the key signal processing technique, i.e., Direction Rotation Alignment technique, the information to be exchanged of the two neighbor OBUs are aligned into a same direction to form summed signal at RSU or external eavesdroppers. With such summed signal, the RSU or the eavesdropper cannot recover the individual information from the OBUs. By regulating the transmission rate for each OBU, the information theoretic security could be achieved. The secrecy sum-rates of the proposed scheme are analyzed following the scheme. Finally, the numerical results are conducted to demonstrate the theoretical analysis.