Hi ,
Attached patch adds cbc mode to the existing code.
Supraja
From 3255d0bbaf31bf3c39b0e22882e52b34882f37d4 Mon Sep 17 00:00:00 2001
From: Supraja Meedinti <supraja0...@gmail.com>
Date: Wed, 17 Dec 2014 10:16:43 +0530
Subject: [PATCH] libavutil: Added cbc mode to cast128
Signed-off-by: Supraja Meedinti <supraja0...@gmail.com>
---
Changelog | 2 +-
libavutil/cast5.c | 45 ++++++++++++++++++++++++++++++++++-----------
libavutil/cast5.h | 2 +-
3 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/Changelog b/Changelog
index 7097a12..59129c0 100644
--- a/Changelog
+++ b/Changelog
@@ -11,7 +11,7 @@ version 2.5:
- HEVC/H.265 RTP payload format (draft v6) packetizer
- SUP/PGS subtitle demuxer
- ffprobe -show_pixel_formats option
-- CAST128 symmetric block cipher, ECB mode
+- CAST128 symmetric block cipher
- STL subtitle demuxer and decoder
- libutvideo YUV 4:2:2 10bit support
- XCB-based screen-grabber
diff --git a/libavutil/cast5.c b/libavutil/cast5.c
index 14dd701..3594e6b 100644
--- a/libavutil/cast5.c
+++ b/libavutil/cast5.c
@@ -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 +439,10 @@ 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);
+ }
AV_WB32(dst, r);
AV_WB32(dst + 4, l);
}
@@ -468,14 +472,21 @@ av_cold int av_cast5_init(AVCAST5* cs, const uint8_t *key, int key_bits)
return 0;
}
-void av_cast5_crypt(AVCAST5* cs, uint8_t* dst, const uint8_t* src, int count, int decrypt)
+void av_cast5_crypt(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);
+ decipher(cs, dst, src, iv);
+ } else {
+ if (iv) {
+ for (i = 0; i < 8; i++)
+ dst[i] = src[i] ^ iv[i];
+ encipher(cs, dst, dst);
} else {
encipher(cs, dst, src);
}
+ }
src = src + 8;
dst = dst + 8;
}
@@ -512,18 +523,18 @@ int main(int argc, char** argv)
cs = av_cast5_alloc();
if (!cs)
return 1;
- for (j = 0; j < 3; j++){
+ for (j = 0; j < 3; j++) {
av_cast5_init(cs, Key[j], key_bits[j]);
- av_cast5_crypt(cs, temp, rpt, 1, 0);
- for (i = 0;i < 8; i++){
- if (rct[j][i] != temp[i]){
+ av_cast5_crypt(cs, temp, rpt, 1, NULL, 0);
+ for (i = 0;i < 8; i++) {
+ if (rct[j][i] != temp[i]) {
av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct[j][i], temp[i]);
err = 1;
}
}
- av_cast5_crypt(cs, temp, rct[j], 1, 1);
+ av_cast5_crypt(cs, temp, rct[j], 1, NULL, 1);
for (i =0; i < 8; i++) {
if (rpt[i] != temp[i]) {
av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
@@ -533,11 +544,11 @@ int main(int argc, char** argv)
}
memcpy(rpt2[0], Key[0], 16);
memcpy(rpt2[1], Key[0], 16);
- for (i = 0; i < 1000000; i++){
+ for (i = 0; i < 1000000; i++) {
av_cast5_init(cs, rpt2[1], 128);
- av_cast5_crypt(cs, rpt2[0], rpt2[0], 2, 0);
+ av_cast5_crypt(cs, rpt2[0], rpt2[0], 2, NULL, 0);
av_cast5_init(cs, rpt2[0], 128);
- av_cast5_crypt(cs, rpt2[1], rpt2[1], 2, 0);
+ av_cast5_crypt(cs, rpt2[1], rpt2[1], 2, NULL, 0);
}
for (j = 0; j < 2; j++) {
for (i = 0; i < 16; i++) {
@@ -547,6 +558,18 @@ int main(int argc, char** argv)
}
}
}
+ for (j = 0; j < 3; j++) {
+
+ av_cast5_init(cs, Key[j], key_bits[j]);
+ av_cast5_crypt(cs, temp, rpt, 1, rct2[0], 0);
+ av_cast5_crypt(cs, temp, temp, 1, rct2[0], 1);
+ for (i =0; i < 8; i++) {
+ if (rpt[i] != temp[i]) {
+ av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
+ err = 1;
+ }
+ }
+ }
av_free(cs);
return err;
}
diff --git a/libavutil/cast5.h b/libavutil/cast5.h
index 913d048..ce758f4 100644
--- a/libavutil/cast5.h
+++ b/libavutil/cast5.h
@@ -60,7 +60,7 @@ int av_cast5_init(struct AVCAST5 *ctx, const uint8_t *key, int key_bits);
* @param count number of 8 byte blocks
* @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);
+void av_cast5_crypt(struct AVCAST5 *ctx, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
/**
* @}
*/
--
1.8.3.2
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