NAME    [Toc]    [Back]

       rc4, RC4_set_key, RC4 - RC4 encryption

SYNOPSIS    [Toc]    [Back]

       #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    [Toc]    [Back]

       This  library  implements the Alleged RC4 cipher, which is
       described in Applied Cryptography.  It is believed  to  be
       compatible  with <trademark>RC4</trademark>, 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.

       The RC4_set_key() function sets up the RC4_KEY  key  using
       the len bytes long key at data.

       The  RC4()  function 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  XORed  with  a
       pseudo-random  key  stream to produce the output), decryption
 uses the same function calls as encryption.

       Applications  should  use  the  higher   level   functions
       instead  of  calling  the  RC4  functions  directly.  (See
       EVP_EncryptInit(3).)

NOTES    [Toc]    [Back]

       Certain conditions have to be  observed  to  securely  use
       stream  ciphers.   You cannot perform multiple encryptions
       using the same key stream.

RETURN VALUES    [Toc]    [Back]

       The RC4_set_key() and RC4() functions do not  return  values.

HISTORY    [Toc]    [Back]

       The RC4_set_key() and RC4() functions are available in all
       versions of SSLeay and OpenSSL.

SEE ALSO    [Toc]    [Back]

       Functions: blowfish(3), des(3), rc2(3)



                                                           rc4(3)