Abstract
Secure storage systems should consider the integrity and authentication of long-term stored information. When information is transferred through communication channels, different types of digital information can be represented, such as documents, images, and database tables. The authenticity of such information must be verified, especially when it is transferred through communication channels. Authentication verification techniques are used to verify that the information in an archive is authentic and has not been intentionally or maliciously altered. In addition to detecting malicious attacks, verifying the integrity also identifies data corruption. The purpose of Message Authentication Code (MAC) is to authenticate messages, where MAC algorithms are keyed hash functions. In most cases, MAC techniques use iterated hash functions, and these techniques are called iterated MACs. Such techniques usually use a MAC key as an input to the compression function, and this key is involved in the compression function, f, at every stage. Modification detection codes (MDCs) are un-keyed hash functions, and are widely used by authentication techniques such as MD4, MD5, SHA-1, and RIPEMD-160. There have been new attacks on hash functions such as MD5 and SHA-1, which requires the introduction of more secure hash functions. In this paper, we introduce a new MAC methodology that uses an input MAC key in the compression function, to change the order of the message words and shifting operation in the compression function. The new methodology can be used in conjunction with a wide range of modification detection code techniques. Using the SHA-1 algorithm as a model, a new (SHA-1)-MAC algorithm is presented. The (SHA-1)-MAC algorithm uses the MAC key to build the hash functions by defining the order for accessing source words and defining the number of bit positions for circular left shifts.