Chaocipher is a method of encryption invented by John F. Byrne in 1918 that was never publicly solved.
The algorithm was published in May 2010. These implementations are based on a paper by Moshe Rubin.
Load the chao.html in a browser. Enter the left and right alphabets. Enter either the plaintext or the ciphertext and click "Encrypt" or "Decrypt" respectively.
The python program chao.py reads the plaintext or ciphertext from
standard input and writes the result to stdout. The left and right
alphabets are set using the --left and --right arguments
respectively. The --encrypt and --decrypt arguments specify the
mode.
An example of encrypting a file: cat myfile | ./chao.py --encrypt --left HXUCZVAMDSLKPEFJRIGTWOBNYQ --right PTLNBQDEOYSFAVZKGJRIHWXUMC
An example of decrypting text entered from the terminal: ./chao.py --decrypt --left HXUCZVAMDSLKPEFJRIGTWOBNYQ --right PTLNBQDEOYSFAVZKGJRIHWXUMC