JCryptor
JCryptor is an encrypting tool based on the Caesar-cipher.
...Caesar-cipher is a simple encryption algorithm, developed by Julius Caesar, to encrypt his correspondence with Cicero in the ancient world. Therefore it uses a simple character substitution method to replace a given character by another. A keyshift of thirteen is called ROT13. ROT13 can be decrypted by encrypting it again with ROT13. Even today this simple method is used by authorities to protect documents from unintentional reading.
--UPDATE--
[25.01.14] Release 1.0 (final)
-- Bugfixes
[05.05.12] Release 0.2
-- implements polyalphabeticel substitution