CryptoToolJ is an extensible
Java application program for creating and anlyzing historical ciphers.
CryptoToolJ can be used as is to create the following kinds of
ciphers: simple substitution, Caesar,
transposition, Vigenere, affine, poly
substitution, and Playfair. It contains cryptanalysis
programs that automatically break most substitution, Caesar,
affine, and Vigenere ciphers.
CryptoToolJ has a plugin capability that enables you
to write your own cipher engines and analyzers that can be
added to CryptoToolJ without recompiling it. This download
include HcryptoJ, plus source code and online documentation.