Mok-Kong Shen mok-kong.shen at
Fri Jun 16 17:20:49 EDT 2017

In classical crypto, homophonic substitution attempts to mitigate risks of
frequency analysis via employing one-to-many mappings of plaintext
characters to ciphertext characters instead of one-to-one mappings.
However, constraints of manual processing naturally very severely limit
the extent to which the flattening of the frequency distributions of the
ciphertext characters could be achieved, which obviously is on the other
hand a non-issue for computer processing. I have written a Python code
HOMOPHONE-SP for performing homophonic substitution (in combination
with transpositions) where, for obtaining higher security, the processing
of the individual plaintext characters is chained via borrowing an idea
from modern block ciphers. The software is available at

M. K. Shen

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