The RC4 encryption algorithm (Menu Crypt/Decrypt \ Symmetric (modern))

RC4 is an encryption algorithm with variable key length that was developed by Ron Rivest in 1987. The algorithm remained secret for seven years. Further information could only be obtained after signing a confidentiality agreement. In 1994 someone published the source code in the Cypherpunks mailing list anonymously. From that time on it became known all round the world.

The key is entered in the Key entry dialog.

CrypTool contains a tool which performs a Brute-force attack on the RC4 encryption algorithm.