libavutil/des.c File Reference

#include <inttypes.h>
#include "avutil.h"
#include "common.h"
#include "intreadwrite.h"
#include "des.h"

Go to the source code of this file.

Defines
#define	T(a, b, c, d, e, f, g, h)   64-a,64-b,64-c,64-d,64-e,64-f,64-g,64-h
#define	T(a, b, c, d)   32-a,32-b,32-c,32-d
#define	T(a, b, c, d, e, f, g)   64-a,64-b,64-c,64-d,64-e,64-f,64-g
#define	T(a, b, c, d, e, f)   56-a,56-b,56-c,56-d,56-e,56-f
Typedefs
typedef struct AVDES	AVDES
Functions
static uint64_t	shuffle (uint64_t in, const uint8_t *shuffle, int shuffle_len)
static uint64_t	shuffle_inv (uint64_t in, const uint8_t *shuffle, int shuffle_len)
static uint32_t	f_func (uint32_t r, uint64_t k)
static uint64_t	key_shift_left (uint64_t CDn)
	rotate the two halves of the expanded 56 bit key each 1 bit left
static void	gen_roundkeys (uint64_t K[16], uint64_t key)
static uint64_t	des_encdec (uint64_t in, uint64_t K[16], int decrypt)
int	av_des_init (AVDES *d, const uint8_t *key, int key_bits, int decrypt)
	Initializes an AVDES context.
void	av_des_crypt (AVDES *d, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt)
	Encrypts / decrypts using the DES algorithm.
Variables
static const uint8_t	IP_shuffle []
static const uint8_t	P_shuffle []
static const uint8_t	PC1_shuffle []
static const uint8_t	PC2_shuffle []
static const uint32_t	S_boxes_P_shuffle [8][64]
	This table contains the results of applying both the S-box and P-shuffle.

---

Define Documentation

#define T	(	a,
		b,
		c,
		d,
		e,
		f		)	56-a,56-b,56-c,56-d,56-e,56-f

Definition at line 68 of file des.c.

#define T	(	a,
		b,
		c,
		d,
		e,
		f,
		g		)	64-a,64-b,64-c,64-d,64-e,64-f,64-g

Definition at line 68 of file des.c.

#define T	(	a,
		b,
		c,
		d		)	32-a,32-b,32-c,32-d

Definition at line 68 of file des.c.

#define T	(	a,
		b,
		c,
		d,
		e,
		f,
		g,
		h		)	64-a,64-b,64-c,64-d,64-e,64-f,64-g,64-h

Definition at line 68 of file des.c.

---

Typedef Documentation

typedef struct AVDES AVDES

Definition at line 27 of file des.c.

---

Function Documentation

void av_des_crypt	(	struct AVDES *	d,
		uint8_t *	dst,
		const uint8_t *	src,
		int	count,
		uint8_t *	iv,
		int	decrypt
	)

Encrypts / decrypts using the DES algorithm.

Parameters:

	count	number of 8 byte blocks
	dst	destination array, can be equal to src, must be 8-byte aligned
	src	source array, can be equal to dst, must be 8-byte aligned, may be NULL
	iv	initialization vector for CBC mode, if NULL then ECB will be used, must be 8-byte aligned
	decrypt	0 for encryption, 1 for decryption

Definition at line 299 of file des.c.

Referenced by ff_asfcrypt_dec().

int av_des_init	(	struct AVDES *	d,
		const uint8_t *	key,
		int	key_bits,
		int	decrypt
	)

Initializes an AVDES context.

Parameters:

	key_bits	must be 64 or 192
	decrypt	0 for encryption, 1 for decryption

Definition at line 287 of file des.c.

Referenced by ff_asfcrypt_dec().

static uint64_t des_encdec	(	uint64_t	in,
		uint64_t	K[16],
		int	decrypt
	)			[static]

Definition at line 269 of file des.c.

Referenced by av_des_crypt().

static uint32_t f_func	(	uint32_t	r,
		uint64_t	k
	)			[static]

Definition at line 217 of file des.c.

Referenced by des_encdec().

static void gen_roundkeys	(	uint64_t	K[16],
		uint64_t	key
	)			[static]

Definition at line 256 of file des.c.

Referenced by av_des_init().

static uint64_t key_shift_left

(

uint64_t

CDn

)

[static]

rotate the two halves of the expanded 56 bit key each 1 bit left

Note: the specification calls this "shift", so I kept it although it is confusing.

Definition at line 248 of file des.c.

Referenced by gen_roundkeys().

static uint64_t shuffle	(	uint64_t	in,
		const uint8_t *	shuffle,
		int	shuffle_len
	)			[static]

Definition at line 198 of file des.c.

Referenced by des_encdec(), f_func(), and gen_roundkeys().

static uint64_t shuffle_inv	(	uint64_t	in,
		const uint8_t *	shuffle,
		int	shuffle_len
	)			[static]

Definition at line 206 of file des.c.

Referenced by des_encdec().

---

Variable Documentation

const uint8_t IP_shuffle[] [static]

Initial value:

 {
    T(58, 50, 42, 34, 26, 18, 10, 2),
    T(60, 52, 44, 36, 28, 20, 12, 4),
    T(62, 54, 46, 38, 30, 22, 14, 6),
    T(64, 56, 48, 40, 32, 24, 16, 8),
    T(57, 49, 41, 33, 25, 17,  9, 1),
    T(59, 51, 43, 35, 27, 19, 11, 3),
    T(61, 53, 45, 37, 29, 21, 13, 5),

}

Definition at line 30 of file des.c.

Referenced by des_encdec().

const uint8_t P_shuffle[] [static]

Initial value:

 {
    T(16,  7, 20, 21),
    T(29, 12, 28, 17),
    T( 1, 15, 23, 26),
    T( 5, 18, 31, 10),
    T( 2,  8, 24, 14),
    T(32, 27,  3,  9),
    T(19, 13, 30,  6),

}

Definition at line 43 of file des.c.

Referenced by f_func().

const uint8_t PC1_shuffle[] [static]

Initial value:

 {
    T(57, 49, 41, 33, 25, 17,  9),
    T( 1, 58, 50, 42, 34, 26, 18),
    T(10,  2, 59, 51, 43, 35, 27),
    T(19, 11,  3, 60, 52, 44, 36),
    T(63, 55, 47, 39, 31, 23, 15),
    T( 7, 62, 54, 46, 38, 30, 22),
    T(14,  6, 61, 53, 45, 37, 29),

}

Definition at line 56 of file des.c.

Referenced by gen_roundkeys().

const uint8_t PC2_shuffle[] [static]

Initial value:

 {
    T(14, 17, 11, 24,  1,  5),
    T( 3, 28, 15,  6, 21, 10),
    T(23, 19, 12,  4, 26,  8),
    T(16,  7, 27, 20, 13,  2),
    T(41, 52, 31, 37, 47, 55),
    T(30, 40, 51, 45, 33, 48),
    T(44, 49, 39, 56, 34, 53),

}

Definition at line 69 of file des.c.

Referenced by gen_roundkeys().

const uint32_t S_boxes_P_shuffle[8][64] [static]

This table contains the results of applying both the S-box and P-shuffle.

It can be regenerated by compiling this file with -DCONFIG_SMALL -DTEST -DGENTABLES

Definition at line 114 of file des.c.

Referenced by f_func().