Abstract

This study contributes a dynamic data blocking mechanism to replace the fixed (static) data blocking mechanism in symmetric cryptosystems. The robustness of cryptosystems relies on dynamicity and probability to provide sufficient randomness. Any encryption method is considered as secure as it retains randomness properties. Current cryptographic algorithms (AES, DES) utilize fixed (static) data blocking mechanism that enable practical cracking of DES and academic cracking of AES-256 up to full 14 rounds with almost practical complexity of (q.267) queries through related-key distinguisher attack which works for 1 key out of 235 keys with 2120 data and time complexity trials. Fixed (static) data blocking mechanism triggers the applicability of this kind of security attacks on symmetric cryptosystems by offering computable probability range. In this study, we proposed a dynamic (variable) data blocking mechanism to achieve robust probabilistic randomness in computing of number of data blocks and their number of bits in symmetric cryptosystems for the enhancement of security strength. The ultimate objective behind this proposed dynamic data blocking mechanism is to produce different number of data blocks with different number of bits in order to lead the complexity (probability) of block partitioning as a NP-hard problem (P ≠ NP - widely believed for which no efficient algorithm exists). In our proposed scheme the diversity of both parameters (block numbers, block bits) is dependent on a plaintext data and key. We applied superlative tactics of digital logic and mathematics in order to evaluate and justify our proposed Dynamic Data Blocking Mechanism (DDBM).

Keywords:

Brute force attack, cryptographic algorithms, decryption, dynamic data blocking mechanism, symmetric encryption,

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The authors have no competing interests.

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