PN-HASH: An Immune-Inspired Scheme for Data Integrity Check

Cryptographic hash functions play significant roles in information security applications, including data integrity. Facing hash collision attacks, several prevalent cryptographic hash functions have been proved not safe enough. In this paper, we propose a simple scheme for data integrity check called PN-HASH (Positive hash and Negative hash). PN-HASH is inspired by the negative representation of information, which is a research branch in the field of immune computation. This scheme computes two hash values of the input message and its negative representation. The resulting hashes are called the positive hash and the negative hash, respectively. The proposed scheme is simple but can improve the resistance to hash collision attacks. Furthermore, for more flexibility and higher security, we propose three extensions of PN-HASH. Security and complexity analyses show that PN-HASH could improve the security of underlying cryptographic hash functions, with approximately twice cost of them. To give exact examples, we present PN-MD5, an implementation of PN-HASH based on MD5.