NAME
RC4_set_key, RC4
— RC4 encryption
SYNOPSIS
#include
<openssl/rc4.h>
void
RC4_set_key(RC4_KEY *key,
int len, const unsigned char
*data);
void
RC4(RC4_KEY *key,
unsigned long len, const unsigned char
*indata, unsigned char *outdata);
DESCRIPTION
This library implements the alleged RC4 cipher, which is described for example in "Applied Cryptography". It is believed to be compatible with RC4[TM], a proprietary cipher of RSA Security Inc.RC4 is a stream cipher with variable key length. Typically, 128-bit (16-byte) keys are used for strong encryption, but shorter insecure key sizes have been widely used due to export restrictions.
RC4 consists of a key setup phase and the actual encryption or decryption phase.
RC4_set_key()
sets up the RC4_KEY key using
the len bytes long key at
data.
RC4()
encrypts or decrypts the len bytes of data at
indata using key and places the
result at outdata. Repeated
RC4() calls with the same key
yield a continuous key stream.
Since RC4 is a stream cipher (the input is XOR'ed with a pseudo-random key stream to produce the output), decryption uses the same function calls as encryption.
SEE ALSO
HISTORY
RC4_set_key() and
RC4() appeared in SSLeay 0.4 or earlier and have
been available since OpenBSD 2.4.
BUGS
This cipher is broken and should no longer be used.