Commit c236e66d authored by Ulf Möller's avatar Ulf Möller
Browse files

Document RC4.

parent 981b87f7

crypto/rc4/rc4.h

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Changes for crypto/rc4/rc4.h: 2 added lines, 2 removed lines.
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@@ -77,8 +77,8 @@ typedef struct rc4_key_st 


 

const char *RC4_options(void);

void RC4_set_key(RC4_KEY *key, int len, unsigned char *data);

void RC4(RC4_KEY *key, unsigned long len, unsigned char *indata,

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);



#ifdef  __cplusplus

crypto/rc4/rc4_enc.c

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Changes for crypto/rc4/rc4_enc.c: 1 added line, 1 removed line.
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 * Date: Wed, 14 Sep 1994 06:35:31 GMT

 */



void RC4(RC4_KEY *key, unsigned long len, unsigned char *indata,

void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata,

	     unsigned char *outdata)

	{

        register RC4_INT *d;

crypto/rc4/rc4_skey.c

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Changes for crypto/rc4/rc4_skey.c: 1 added line, 1 removed line.
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@@ -85,7 +85,7 @@ const char *RC4_options(void) 
 * Date: Wed, 14 Sep 1994 06:35:31 GMT

 */



void RC4_set_key(RC4_KEY *key, int len, register unsigned char *data)

void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)

	{

        register RC4_INT tmp;

        register int id1,id2;

doc/crypto/rc4.pod

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Changes for doc/crypto/rc4.pod: 58 added lines, 0 removed lines.
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=pod



=head1 NAME



RC4_set_key, RC4 - RC4 encryption



=head1 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);



=head1 DESCRIPTION



This library implements the Alleged RC4 cipher, which is described for

example in I<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 B<RC4_KEY> B<key> using the B<len> bytes long

key at B<data>.



RC4() encrypts or decrypts the B<len> bytes of data at B<indata> using

B<key> and places the result at B<outdata>.  Repeated RC4() calls with

the same B<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.



=head1 RETURN VALUES



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



=head1 NOTE



Certain conditions have to be observed to securely use stream ciphers.

It is not permissible to perform multiple encryptions using the same

key stream.



=head1 SEE ALSO



L<blowfish(3)|blowfish(3)>, L<des(3)|des(3)>, L<rc2(3)|rc2(3)>



=head1 HISTORY



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



=cut