On the padding algorithm of large-sized blocks in integrity control systems

In integrity check value algorithms, calculating the checksum of a file requires that its length be a multiple of a given value ($l$ bits). When file size of any length is used to be checked, the file is usually padded to the required length. A computationally simple and efficient padding scheme, designed for integrity control systems processing large blocks (about $1$ Kbyte), is presented. The scheme is based on the outputs of a linear congruent generator. The initial state of the generator is formed with the data of the block to be padded and the length of the file. The results of analysis of cryptographic properties of the integrity control algorithm and performance evaluation experiments showed the comparative advantages of the proposed scheme in comparison with the known standard padding schemes.