RC4 Class Reference

#include <rc4.h>

Inheritance diagram for RC4:

Collaboration diagram for RC4:

---

Detailed Description

Implementation of the RC4 stream cipher.

The ISC implementation of RC4 is compatible with RSADSI RC4, and with the cipher that the US State Dept. calls RC4; it is also known as "alleged RC4" and ARCFOUR.

Usage flow:
  RC4()    // instantiate a new RC4 object
  init()   // specify the key
  crypt()  // perform the encrypt or decrypt operation


Recommendations for strict FIPS 140-1 compliance:
  RC4 is not a FIPS approved algorithm, so the RC4 class should 
  *NOT* be used.

Sample code illustrating the use of this class appears in the Cookbook section Using the Symmetric Ciphers.

References

RC4 is specified and discussed in:

• RFC 2246

• IETF ID "Arcfour"

• J. Golic, "Linear statistical weakness of alleged RC4 keystream generator," Advances in Cryptology, Proceedings Eurocrypt'97, LNCS 1233, W. Fumy, Ed., Springer-Verlag, 1997, pp. 226--238.

• CipherSaber has an english language description of RC4 at: http://ciphersaber.gurus.com/faq.html#getrc4

• B. Schneier, Applied Cryptography, 2^nd ed., John Wiley & Sons, 1996.

Public Member Functions
	RC4 ()
	Constructor. Calls init().
	~RC4 ()
	Destructor. Calls init().
int	init ()
	Initialize the RC4 object.
int	init (int len, const char *key)
	Initialize the RC4 object and load a new key.
int	add (int len, const char *b)
	Update the permutation controlling the internal pseudorandom number generator.
int	crypt (int len, const char *src, char *dest)
	Encrypt or decrypt a specified buffer.
int	gen ()
	Generate one pseudorandom byte.

---

Member Function Documentation

int add	(	int	len,
		const char *	b
	)

Update the permutation controlling the internal pseudorandom number generator.

Parameters:

	len	the length in bytes of the input buffer
	b	a pointer to the input buffer

Returns:

0 (success)
CDK_ERROR_STATE CDK_INVALID_PTR

int crypt	(	int	len,
		const char *	src,
		char *	dest
	)

Encrypt or decrypt a specified buffer.

Parameters:

	len	the length of the input and output buffers in bytes
	src	a pointer to the input buffer
	dest	a pointer to the output buffer

Returns:

0 (success)
CDK_ERROR_STATE CDK_INVALID_PTR

int gen

(

)

Generate one pseudorandom byte.

Returns:

a single byte from the internal pseudorandom number generator.

int init	(	int	len,
		const char *	key
	)

Initialize the RC4 object and load a new key.

Parameters:

	len	the length of key in bytes
	key	a pointer to the new key

Remarks:

All key material is reset, then add() is called to update the permutation controlling the internal pseudorandom number generator.

Returns:

0 (success)
CDK_ERROR_STATE
CDK_INVALID_PTR

int init

(

)

Initialize the RC4 object.

Returns:

0 (success)
CDK_ERROR_STATE

Remarks:

This function resets the RC4 object to its initial state, zeroizing all key material.

---

The documentation for this class was generated from the following file:

• rc4.h

---

ISC Cryptographic Development Kit - User's Guide
Questions? E-mail ISC technical support
Copyright© 2002-2006 Information Security Corp. All rights reserved.