[FFmpeg-cvslog] xtea: Add functions for little endian mode
Martin Storsjö
git at videolan.org
Sun Nov 22 15:37:26 CET 2015
ffmpeg | branch: master | Martin Storsjö <martin at martin.st> | Wed Nov 11 22:09:41 2015 +0200| [92d107a17127c29036b71e53315a2c702960819a] | committer: Martin Storsjö
xtea: Add functions for little endian mode
Signed-off-by: Martin Storsjö <martin at martin.st>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=92d107a17127c29036b71e53315a2c702960819a
---
doc/APIchanges | 3 ++
libavutil/version.h | 2 +-
libavutil/xtea.c | 94 ++++++++++++++++++++++++++++++++++++++++++++-------
libavutil/xtea.h | 23 +++++++++++++
4 files changed, 108 insertions(+), 14 deletions(-)
diff --git a/doc/APIchanges b/doc/APIchanges
index cc48b51..206796e 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -12,6 +12,9 @@ libavutil: 2015-08-28
API changes, most recent first:
+2015-11-xx - xxxxxxx - lavu 55.3.0 - xtea.h
+ Add av_xtea_le_init and av_xtea_le_crypt
+
2015-11-xx - xxxxxxx - lavfi 6.1.0 - avfilter.h
Add a frame_rate field to AVFilterLink
diff --git a/libavutil/version.h b/libavutil/version.h
index 14a1ded..7131122 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -54,7 +54,7 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 55
-#define LIBAVUTIL_VERSION_MINOR 2
+#define LIBAVUTIL_VERSION_MINOR 3
#define LIBAVUTIL_VERSION_MICRO 0
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
diff --git a/libavutil/xtea.c b/libavutil/xtea.c
index 43ba8fc..25fd2f0 100644
--- a/libavutil/xtea.c
+++ b/libavutil/xtea.c
@@ -53,6 +53,14 @@ void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
ctx->key[i] = AV_RB32(key + (i << 2));
}
+void av_xtea_le_init(AVXTEA *ctx, const uint8_t key[16])
+{
+ int i;
+
+ for (i = 0; i < 4; i++)
+ ctx->key[i] = AV_RL32(key + (i << 2));
+}
+
static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int decrypt, uint8_t *iv)
{
@@ -89,14 +97,51 @@ static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
AV_WB32(dst + 4, v1);
}
-void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
- uint8_t *iv, int decrypt)
+static void xtea_le_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
+ int decrypt, uint8_t *iv)
+{
+ uint32_t v0, v1;
+ int i;
+
+ v0 = AV_RL32(src);
+ v1 = AV_RL32(src + 4);
+
+ if (decrypt) {
+ uint32_t delta = 0x9E3779B9, sum = delta * 32;
+
+ for (i = 0; i < 32; i++) {
+ v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
+ sum -= delta;
+ v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
+ }
+ if (iv) {
+ v0 ^= AV_RL32(iv);
+ v1 ^= AV_RL32(iv + 4);
+ memcpy(iv, src, 8);
+ }
+ } else {
+ uint32_t sum = 0, delta = 0x9E3779B9;
+
+ for (i = 0; i < 32; i++) {
+ v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
+ sum += delta;
+ v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
+ }
+ }
+
+ AV_WL32(dst, v0);
+ AV_WL32(dst + 4, v1);
+}
+
+static void xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
+ uint8_t *iv, int decrypt,
+ void (*crypt)(AVXTEA *, uint8_t *, const uint8_t *, int, uint8_t *))
{
int i;
if (decrypt) {
while (count--) {
- xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
+ crypt(ctx, dst, src, decrypt, iv);
src += 8;
dst += 8;
@@ -106,10 +151,10 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
if (iv) {
for (i = 0; i < 8; i++)
dst[i] = src[i] ^ iv[i];
- xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
+ crypt(ctx, dst, dst, decrypt, NULL);
memcpy(iv, dst, 8);
} else {
- xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
+ crypt(ctx, dst, src, decrypt, NULL);
}
src += 8;
dst += 8;
@@ -117,6 +162,18 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
}
}
+void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
+ uint8_t *iv, int decrypt)
+{
+ xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_crypt_ecb);
+}
+
+void av_xtea_le_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
+ uint8_t *iv, int decrypt)
+{
+ xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_le_crypt_ecb);
+}
+
#ifdef TEST
#include <stdio.h>
@@ -157,9 +214,10 @@ static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
const uint8_t *ref, int len, uint8_t *iv, int dir,
- const char *test)
+ const char *test,
+ void (*crypt)(AVXTEA *, uint8_t *, const uint8_t *, int, uint8_t *, int))
{
- av_xtea_crypt(ctx, dst, src, len, iv, dir);
+ crypt(ctx, dst, src, len, iv, dir);
if (memcmp(dst, ref, 8*len)) {
int i;
printf("%s failed\ngot ", test);
@@ -176,8 +234,8 @@ static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int main(void)
{
AVXTEA ctx;
- uint8_t buf[8], iv[8];
- int i;
+ uint8_t buf[16], iv[8];
+ int i, j;
const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
uint8_t ct[32];
uint8_t pl[32];
@@ -185,8 +243,18 @@ int main(void)
for (i = 0; i < XTEA_NUM_TESTS; i++) {
av_xtea_init(&ctx, xtea_test_key[i]);
- test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
- test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
+ test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption", av_xtea_crypt);
+ test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption", av_xtea_crypt);
+
+ for (j = 0; j < 4; j++)
+ AV_WL32(&buf[4*j], AV_RB32(&xtea_test_key[i][4*j]));
+ av_xtea_le_init(&ctx, buf);
+ for (j = 0; j < 2; j++) {
+ AV_WL32(&ct[4*j], AV_RB32(&xtea_test_ct[i][4*j]));
+ AV_WL32(&pl[4*j], AV_RB32(&xtea_test_pt[i][4*j]));
+ }
+ test_xtea(&ctx, buf, pl, ct, 1, NULL, 0, "encryption", av_xtea_le_crypt);
+ test_xtea(&ctx, buf, ct, pl, 1, NULL, 1, "decryption", av_xtea_le_crypt);
/* encrypt */
memcpy(iv, "HALLO123", 8);
@@ -194,10 +262,10 @@ int main(void)
/* decrypt into pl */
memcpy(iv, "HALLO123", 8);
- test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
+ test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption", av_xtea_crypt);
memcpy(iv, "HALLO123", 8);
- test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
+ test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption", av_xtea_crypt);
}
printf("Test encryption/decryption success.\n");
diff --git a/libavutil/xtea.h b/libavutil/xtea.h
index ad76955..78b1f37 100644
--- a/libavutil/xtea.h
+++ b/libavutil/xtea.h
@@ -55,6 +55,15 @@ AVXTEA *av_xtea_alloc(void);
void av_xtea_init(struct AVXTEA *ctx, const uint8_t key[16]);
/**
+ * Initialize an AVXTEA context.
+ *
+ * @param ctx an AVXTEA context
+ * @param key a key of 16 bytes used for encryption/decryption,
+ * interpreted as little endian 32 bit numbers
+ */
+void av_xtea_le_init(struct AVXTEA *ctx, const uint8_t key[16]);
+
+/**
* Encrypt or decrypt a buffer using a previously initialized context,
* in big endian format.
*
@@ -69,6 +78,20 @@ void av_xtea_crypt(struct AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt);
/**
+ * Encrypt or decrypt a buffer using a previously initialized context,
+ * in little endian format.
+ *
+ * @param ctx an AVXTEA 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, if NULL then ECB will be used
+ * @param decrypt 0 for encryption, 1 for decryption
+ */
+void av_xtea_le_crypt(struct AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
+ int count, uint8_t *iv, int decrypt);
+
+/**
* @}
*/
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