Author:
Magdy Saeb
Affiliation:
Arab Academy for Science, Tech. & Maritime Transport, Alexandria, Egypt / Malaysian Institute of Microelectronic Systems (MIMOS Bhd.), Malaysia
Keyword(s):
Polymorphic cipher, Homophonic, Random walks, Key-driven, Cryptanalysis, Hash function.
Related
Ontology
Subjects/Areas/Topics:
Cryptographic Techniques and Key Management
;
Data and Systems Security
;
Information and Systems Security
;
Ipsec, Vpns and Encryption Modes
;
Public Key Crypto Applications
Abstract:
The Chameleon Cipher-192 is a polymorphic cipher that utilizes a variable word size and variable-size user’s key. In the preprocessing stage, the user key is extended into a larger table or bit-level S-box using a specially developed hash-function. The generated table is used in a special configuration to substantially increase the substitution addressing space. Accordingly, we call this table the S-orb. We show that the proposed cipher provides concepts of key-dependent number of rotations, key-dependent number of rounds and key-dependent addresses of substitution tables. Moreover, the parameters used to generate the different S-orb words are likewise key-dependent. We establish that the self-modifying proposed cipher, based on the aforementioned key-dependencies, provides an algorithm polymorphism and adequate security with a simple parallelizable structure. The ideas incorporated in the development of this cipher may pave the way for key-driven encryption rather than merely using
the key for sub-key generation. The cipher is adaptable to both hardware and software implementations. Potential applications include voice and image encryption.
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