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Add and use a public API for RC4 and DES, analogous to the AES API.

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Originally committed as revision 16970 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reimar Döffinger
2009-02-03 14:20:55 +00:00
parent 88297e80aa
commit 1a534c7f1e
5 changed files with 125 additions and 24 deletions
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13
libavformat/asfcrypt.c
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@@ -136,6 +136,8 @@ static uint64_t multiswap_dec(const uint32_t keys[12], uint64_t key, uint64_t da
}
void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) {
struct AVDES des;
struct AVRC4 rc4;
int num_qwords = len >> 3;
uint64_t *qwords = (uint64_t *)data;
uint64_t rc4buff[8];
@@ -150,17 +152,18 @@ void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) {
}
memset(rc4buff, 0, sizeof(rc4buff));
ff_rc4_enc(key, 12, (uint8_t *)rc4buff, sizeof(rc4buff));
av_rc4_init(&rc4, key, 12 * 8, 1);
av_rc4_crypt(&rc4, (uint8_t *)rc4buff, NULL, sizeof(rc4buff), NULL, 1);
multiswap_init((uint8_t *)rc4buff, ms_keys);
packetkey = qwords[num_qwords - 1];
packetkey ^= rc4buff[7];
packetkey = be2me_64(packetkey);
packetkey = ff_des_encdec(packetkey, AV_RB64(key + 12), 1);
packetkey = be2me_64(packetkey);
av_des_init(&des, key + 12, 64, 1);
av_des_crypt(&des, (uint8_t *)&packetkey, (uint8_t *)&packetkey, 1, NULL, 1);
packetkey ^= rc4buff[6];
ff_rc4_enc((uint8_t *)&packetkey, 8, data, len);
av_rc4_init(&rc4, (uint8_t *)&packetkey, 64, 1);
av_rc4_crypt(&rc4, data, data, len, NULL, 1);
ms_state = 0;
for (i = 0; i < num_qwords - 1; i++, qwords++)