An approach in improving transposition cipher system

Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
Indian Journal of Science and Technology 09/2009; 2(8). DOI: 10.17485/ijst/2009/v2i8/29502


Transposition ciphers are stronger than simple substitution ciphers. However, if the key is short and the message is long, then various cryptanalysis techniques can be applied to break such ciphers. By adding 8 bits (one byte) for each byte using a function and another mathematical function to position the bits in a binary tree and using its in-order tour, this cipher can be made protected. Using an in-order tour of binary tree can diffuse the eight bits (includes 7 bits produced by the function and 1 random bit) and eight bits of the plaintext. This can highly protect the cipher. However, if the key management processes are not secured the strongest ciphers can easily be broken.

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