#include "libavutil/bswap.h"
#include "libavutil/common.h"
#include "libavutil/des.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/rc4.h"
#include "asfcrypt.h"

Functions
static uint32_t	inverse (uint32_t v)
	find multiplicative inverse modulo 2 ^ 32

static void	multiswap_init (const uint8_t keybuf[48], uint32_t keys[12])
	read keys from keybuf into keys

static void	multiswap_invert_keys (uint32_t keys[12])
	invert the keys so that encryption become decryption keys and the other way round.

static uint32_t	multiswap_step (const uint32_t keys[12], uint32_t v)

static uint32_t	multiswap_inv_step (const uint32_t keys[12], uint32_t v)

static uint64_t	multiswap_enc (const uint32_t keys[12], uint64_t key, uint64_t data)
	"MultiSwap" encryption

static uint64_t	multiswap_dec (const uint32_t keys[12], uint64_t key, uint64_t data)
	"MultiSwap" decryption

void	ff_asfcrypt_dec (const uint8_t key[20], uint8_t *data, int len)

Function Documentation

static uint32_t inverse ( uint32_t v )

static

find multiplicative inverse modulo 2 ^ 32

Parameters

v	number to invert, must be odd!

Returns: number so that result * v = 1 (mod 2^32)

Definition at line 35 of file asfcrypt.c.

Referenced by ff_dct_init(), ff_fft_init(), and multiswap_invert_keys().

static void multiswap_init	(	const uint8_t	keybuf[48],
		uint32_t	keys[12]
	)

static

read keys from keybuf into keys

Parameters

keybuf	buffer containing the keys
keys	output key array containing the keys for encryption in native endianness

Definition at line 54 of file asfcrypt.c.

Referenced by ff_asfcrypt_dec().

static void multiswap_invert_keys ( uint32_t keys[12] )

static

invert the keys so that encryption become decryption keys and the other way round.

Parameters

keys	key array of ints to invert

Definition at line 66 of file asfcrypt.c.

Referenced by ff_asfcrypt_dec().

static uint32_t multiswap_step	(	const uint32_t	keys[12],
		uint32_t	v
	)

static

Definition at line 75 of file asfcrypt.c.

Referenced by multiswap_enc().

static uint32_t multiswap_inv_step	(	const uint32_t	keys[12],
		uint32_t	v
	)

static

Definition at line 87 of file asfcrypt.c.

Referenced by multiswap_dec().

static uint64_t multiswap_enc	(	const uint32_t	keys[12],
		uint64_t	key,
		uint64_t	data
	)

static

"MultiSwap" encryption

Parameters

keys	32 bit numbers in machine endianness, 0-4 and 6-10 must be inverted from decryption
key	another key, this one must be the same for the decryption
data	data to encrypt

Returns: encrypted data

Definition at line 107 of file asfcrypt.c.

Referenced by ff_asfcrypt_dec().

static uint64_t multiswap_dec	(	const uint32_t	keys[12],
		uint64_t	key,
		uint64_t	data
	)

static

"MultiSwap" decryption

Parameters

keys	32 bit numbers in machine endianness, 0-4 and 6-10 must be inverted from encryption
key	another key, this one must be the same as for the encryption
data	data to decrypt

Returns: decrypted data

Definition at line 131 of file asfcrypt.c.

Referenced by ff_asfcrypt_dec().

void ff_asfcrypt_dec	(	const uint8_t	key[20],
		uint8_t *	data,
		int	len
	)

Definition at line 147 of file asfcrypt.c.

Referenced by ff_asf_parse_packet().

Functions

Function Documentation