Safe Encoding;Making the encoded text of an instantaneous code as random as possible.

Date of Submission

December 2001

Date of Award

Winter 12-12-2002

Institute Name (Publisher)

Indian Statistical Institute

Document Type

Master's Dissertation

Degree Name

Master of Technology

Subject Name

Computer Science


Applied Statistics Unit (ASU-Kolkata)


Roy, Bimal Kumar (ASU-Kolkata; ISI)

Abstract (Summary of the Work)

We know from information theory that the channel capacity is achieved when the input events are statistically independent and have the same probability distribution and the channel capacity is the maximum amount of information we can send through the channel. Here a padding algorithm is designed which takes any plain text (i.e. message) as input and outputs the corresponding encoding scheme whose encoded text will have the frequencies of strings "00&"01", &","10" "11", close together. This makes the encoded text close to random, since English language can be considered to be a Markov Process of order 1. This also protects against cipher text only attack by transmitting symbols randomly giving almost zero information to the eavesdropper. Without loss of generality, Huffman code is taken as the coding scheme in initial steps to the algorithm. Since the minimum variance code ensures less degradation of the coding scheme in presence of noise, the least skewed Huffman tree is considered. About the closeness bound of the frequencies of strings "00",:"01","10","11" is discussed.


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Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


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