Paper 2014/257
Handycipher: a Low-tech, Randomized, Symmetric-key Cryptosystem
Bruce Kallick
Abstract
Handycipher is a low-tech, randomized, symmetric-key, stream cipher, simple enough to permit pen-and-paper encrypting and decrypting of messages, while providing a significantly high level of security. It combines a simple 31-character substitution cipher with a 3,045-token nondeterministic homophonic substitution cipher, and employs the insertion of randomly chosen decoy characters at random locations in the ciphertext. A deniable encryption scheme based on the cipher is described, as well as a way of extending the cipher by using randomly generated session keys.
Note: The current version has been further strengthened by by adding another ten characters to the ciphertext alphabet, using a 51-character key instead of 41, increasing the number of null characters from 15 to 25, and by interweaving random non-null "noise" characters in the Core-cipher encryption before the null characters are added.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Preprint.
- Keywords
- stream cipherssecret-key cryptographyrandomized homophonic substitutionhand ciphers
- Contact author(s)
- curmudgeon @ rudegnu com
- History
- 2016-02-04: last of 12 revisions
- 2014-04-20: received
- See all versions
- Short URL
- https://ia.cr/2014/257
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2014/257,
author = {Bruce Kallick},
title = {Handycipher: a Low-tech, Randomized, Symmetric-key Cryptosystem},
howpublished = {Cryptology {ePrint} Archive, Paper 2014/257},
year = {2014},
url = {https://eprint.iacr.org/2014/257}
}
