RC4(3)                     Library Functions Manual                     RC4(3)

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
     blowfish(3), EVP_EncryptInit(3), EVP_rc4(3)

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.

Linux 6.8.2-arch2-1             March 29, 2020             Linux 6.8.2-arch2-1