libavutil: Added cbc mode to cast128

Signed-off-by: Supraja Meedinti <supraja0493@gmail.com>
Previous version reviewed-by: Giorgio Vazzana <mywing81@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Supraja Meedinti 2014-12-18 15:26:32 +05:30 committed by Michael Niedermayer
parent bdc1e3e3b2
commit 4e1ecfe214
2 changed files with 55 additions and 3 deletions

View File

@ -416,7 +416,7 @@ static void encipher(AVCAST5* cs, uint8_t* dst, const uint8_t* src)
AV_WB32(dst + 4, l);
}
static void decipher(AVCAST5* cs, uint8_t* dst, const uint8_t* src)
static void decipher(AVCAST5* cs, uint8_t* dst, const uint8_t* src, uint8_t *iv)
{
uint32_t f, I, r, l;
l = AV_RB32(src);
@ -439,6 +439,11 @@ static void decipher(AVCAST5* cs, uint8_t* dst, const uint8_t* src)
F3(r, l, 3);
F2(l, r, 2);
F1(r, l, 1);
if (iv) {
r ^= AV_RB32(iv);
l ^= AV_RB32(iv + 4);
memcpy(iv, src, 8);
}
AV_WB32(dst, r);
AV_WB32(dst + 4, l);
}
@ -468,11 +473,31 @@ av_cold int av_cast5_init(AVCAST5* cs, const uint8_t *key, int key_bits)
return 0;
}
void av_cast5_crypt2(AVCAST5* cs, uint8_t* dst, const uint8_t* src, int count, uint8_t *iv, int decrypt)
{
int i;
while (count--) {
if (decrypt) {
decipher(cs, dst, src, iv);
} else {
if (iv) {
for (i = 0; i < 8; i++)
dst[i] = src[i] ^ iv[i];
encipher(cs, dst, dst);
memcpy(iv, dst, 8);
} else {
encipher(cs, dst, src);
}
}
src = src + 8;
dst = dst + 8;
}
}
void av_cast5_crypt(AVCAST5* cs, uint8_t* dst, const uint8_t* src, int count, int decrypt)
{
while (count--) {
if (decrypt){
decipher(cs, dst, src);
decipher(cs, dst, src, NULL);
} else {
encipher(cs, dst, src);
}
@ -504,6 +529,7 @@ int main(int argc, char** argv)
{0xee, 0xa9, 0xd0, 0xa2, 0x49, 0xfd, 0x3b, 0xa6, 0xb3, 0x43, 0x6f, 0xb8, 0x9d, 0x6d, 0xca, 0x92},
{0xb2, 0xc9, 0x5e, 0xb0, 0x0c, 0x31, 0xad, 0x71, 0x80, 0xac, 0x05, 0xb8, 0xe8, 0x3d, 0x69, 0x6e}
};
const uint8_t iv[8] = {0xee, 0xa9, 0xd0, 0xa2, 0x49, 0xfd, 0x3b, 0xa6};
static uint8_t rpt2[2][16];
int i, j, err = 0;
static int key_bits[3] = {128, 80, 40};
@ -547,6 +573,20 @@ int main(int argc, char** argv)
}
}
}
for (j = 0; j < 3; j++) {
av_cast5_init(cs, Key[j], key_bits[j]);
memcpy(temp, iv, 8);
av_cast5_crypt2(cs, rpt2[0], rct2[0], 2, temp, 0);
memcpy(temp, iv, 8);
av_cast5_crypt2(cs, rpt2[0], rpt2[0], 2, temp, 1);
for (i = 0; i < 16; i++) {
if (rct2[0][i] != rpt2[0][i]) {
av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct2[0][i], rpt2[0][i]);
err = 1;
}
}
}
av_free(cs);
return err;
}

View File

@ -52,7 +52,7 @@ struct AVCAST5 *av_cast5_alloc(void);
int av_cast5_init(struct AVCAST5 *ctx, const uint8_t *key, int key_bits);
/**
* Encrypt or decrypt a buffer using a previously initialized context
* Encrypt or decrypt a buffer using a previously initialized context, ECB mode only
*
* @param ctx an AVCAST5 context
* @param dst destination array, can be equal to src
@ -61,6 +61,18 @@ int av_cast5_init(struct AVCAST5 *ctx, const uint8_t *key, int key_bits);
* @param decrypt 0 for encryption, 1 for decryption
*/
void av_cast5_crypt(struct AVCAST5 *ctx, uint8_t *dst, const uint8_t *src, int count, int decrypt);
/**
* Encrypt or decrypt a buffer using a previously initialized context
*
* @param ctx an AVCAST5 context
* @param dst destination array, can be equal to src
* @param src source array, can be equal to dst
* @param count number of 8 byte blocks
* @param iv initialization vector for CBC mode, NULL for ECB mode
* @param decrypt 0 for encryption, 1 for decryption
*/
void av_cast5_crypt2(struct AVCAST5 *ctx, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
/**
* @}
*/