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This research purpose is to develop a reduction-based method for analysis of cryptographic properties of block cipher modes of operation in context of full disk encryption (FDE) via provable security technique, to study weaknesses of widely spread among existing FDE solutions mode XTS through building an adversary, that breaks security of XTS, and then to create a variation of the mode, that fixes detected weaknesses. This new mode of operation is called XEH (Xor-Encrypt-Hash) and it uses “light-weight” polynomial permutation for mixing blocks of a sector after their “XTS-like” encryption. The proposed block cipher mode of operation does not require any space for additional data, and it allows us to use it for system disk encryption, unlike DEC mode proposed in the end of 2021 by TC 26. XEH was proved to be secure in a provable security model, which is described in this paper. This mode is compared with the existing ones, which can be used to encrypt block-oriented devices: it was shown, that XEH provides higher security bound, than other compared modes, and involves almost no degradation in performance with respect to XTS.

Block symmetric ciphers are an integral part of modern complex information security systems. Today, the attention of researchers is focused on increasing the efficiency and performance of block symmetric ciphers. However, it is shown by the practical experience of implementation of data encryption systems, that block cipher modes of operation are also of great importance for the efficiency and performance of encryption systems. In this paper we propose new block cipher modes of operation: with block skipping, as well as with block skipping and the use of pseudo-random key sequence generator. The proposed block cipher modes of operation make it possible to reduce the amount of used in the program data encryption operations (i.e. the amount of the block symmetric cipher runs). For the developed block cipher modes of operation, the parameters are calculated to ensure a high level of stochastic quality of the obtained ciphertext, which is confirmed by the tests carried out in accordance with the NIST stochastic test suite. At the same time, it was found that the block cipher mode of operation with skipping of blocks and the use of a pseudo-random key sequence generator, provides a significant increase in the number of information protection levels of the applied cryptographic transformation, and also shows the best results when passing the NIST stochastic tests suite. The developed block cipher modes of operation are a reasonable solution for use in applications running on platforms with limited computing and power resources, primarily on mobile platforms. In this case, it is preferable to select a block cipher mode of operation with skipping of blocks and use of pseudo-random key sequence generator. Note also that the presented block cipher modes of operation allow to combine the advantages of block ciphers and generators of pseudorandom key sequences. [ABSTRACT FROM AUTHOR]