rc4.h File Reference

Primitive. More...

#include "ordo/primitives/stream_ciphers.h"

Include dependency graph for rc4.h:

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Functions
ORDO_PUBLIC int	rc4_init (struct RC4_STATE *state, const void *key, size_t key_len, const struct RC4_PARAMS *params)
ORDO_PUBLIC void	rc4_update (struct RC4_STATE *state, void *buffer, size_t len)
ORDO_PUBLIC void	rc4_final (struct RC4_STATE *state)
ORDO_PUBLIC size_t	rc4_query (int query, size_t value)
ORDO_PUBLIC size_t	rc4_bsize (void)

Detailed Description

Primitive.

RC4 is a stream cipher, which accepts keys between 40 and 2048 bits (in multiples of 8 bits only). It accepts a parameter consisting of the number of initial keystream bytes to drop immediately after key schedule, effectively implementing RC4-drop[n]. If no drop parameter is passed, the implementation drops 2048 bytes by default.

Be aware that even with a drop, it isn't secure to encrypt more than a few hundred megabytes of data with the same key (due to a distinguisher attack that can distinguish between an RC4 keystream and a random stream). If you are concerned, use a different algorithm or rekey at generous intervals.

Function Documentation

ORDO_PUBLIC int rc4_init	(	struct RC4_STATE *	state,
		const void *	key,
		size_t	key_len,
		const struct RC4_PARAMS *	params
	)

See Also

stream_init()

Return values

ORDO_KEY_LEN

if the key length was less than 40 bits (5 bytes) or more than 2048 bits (256 bytes).

Remarks

The amount of keystream bytes to drop can be set via the params argument, see RC4_PARAMS. By default, 2048 bytes are dropped.

ORDO_PUBLIC void rc4_update	(	struct RC4_STATE *	state,
		void *	buffer,
		size_t	len
	)

See Also

stream_update()

ORDO_PUBLIC void rc4_final

(

struct RC4_STATE *

state

)

See Also

stream_final()

ORDO_PUBLIC size_t rc4_query	(	int	query,
		size_t	value
	)

See Also

stream_query()

ORDO_PUBLIC size_t rc4_bsize

(

void

)

Gets the size in bytes of an RC4_STATE.

Returns

The size in bytes of the structure.

Remarks

Binary compatibility layer.