RC4 is a symmetric stream cipher developed by Ron Rivest of RSA Data Security Inc. The algorithm was a trade secret of RSA but was reverse engineered and published to the internet in 1994. RC4 is vulnerable to various attacks, and is considered insecure.
PT 2004-07-01
The algorithm is a pseudo-random number generator with the output of the PRNG being xored with the plaintext stream. Decryption is done by feeding the ciphertext as input with the same key.
This cipher is included as a package in tcllib
e.g:
set src [open $filename r]
set dst [open ${filename}.rc4 w]
rc4::rc4 -key Secret -in $src -out $dst
close $src
close $dstor just
set crypt [rc4::rc4 -key Secret {Hello, World!}]