NAME

setupRC4state, rc4, rc4skip, rc4back  - alleged rc4 encryption

SYNOPSIS

­#include <u.h>
­#include <libc.h>
­#include <mp.h>
­#include <libsec.h>

voidsetupRC4state(RC4state ∗s, uchar ∗seed, int slen)

voidrc4(RC4state ∗s, uchar ∗data, int dlen)

voidrc4skip(RC4state ∗s, int nbytes)

voidrc4back(RC4state ∗s, int nbytes)

DESCRIPTION

This is an algorithm alleged to be Rivest’s RC4 encryption function.  It is a pseudo-random number generator with a 256 byte state and a long cycle.  The input buffer is XOR’d with the output of the generator both to encrypt and to decrypt.  The seed, entered using setupRC4state, can be any length.  The generator can be run forward using rc4, skip over bytes using ­rc4skip to account lost transmissions, or run backwards using ­rc4back to cover retransmitted data.  The ­RC4state structure keeps track of the algorithm. 

SOURCE

­/sys/src/libsec

SEE ALSO

mp(2), aes(2), blowfish(2), des(2), dsa(2), elgamal(2), rsa(2), sechash(2), prime(2), rand(2)

Plan 9  —  September 14, 2002