* RC4 encryption/decryption/pseudo-random number generator
* Copyright (c) 2007 Reimar Doeffinger
*
- * This file is part of FFmpeg.
+ * loosely based on LibTomCrypt by Tom St Denis
+ *
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * loosely based on LibTomCrypt by Tom St Denis
*/
+#include "avutil.h"
#include "common.h"
+#include "mem.h"
#include "rc4.h"
-void ff_rc4_enc(const uint8_t *key, int keylen, uint8_t *data, int datalen) {
- int i, j;
- uint8_t x, y;
+#if !FF_API_CRYPTO_CONTEXT
+struct AVRC4 {
uint8_t state[256];
+ int x, y;
+};
+#endif
+
+AVRC4 *av_rc4_alloc(void)
+{
+ return av_mallocz(sizeof(struct AVRC4));
+}
+
+int av_rc4_init(AVRC4 *r, const uint8_t *key, int key_bits, int decrypt) {
+ int i, j;
+ uint8_t y;
+ uint8_t *state = r->state;
+ int keylen = key_bits >> 3;
+ if (key_bits & 7)
+ return -1;
for (i = 0; i < 256; i++)
state[i] = i;
y = 0;
y += state[i] + key[j];
FFSWAP(uint8_t, state[i], state[y]);
}
- // state initialized, now do the real encryption
- x = 1; y = state[1];
- while (datalen-- > 0) {
+ r->x = 1;
+ r->y = state[1];
+ return 0;
+}
+
+void av_rc4_crypt(AVRC4 *r, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt) {
+ uint8_t x = r->x, y = r->y;
+ uint8_t *state = r->state;
+ while (count-- > 0) {
uint8_t sum = state[x] + state[y];
FFSWAP(uint8_t, state[x], state[y]);
- *data++ ^= state[sum];
+ *dst++ = src ? *src++ ^ state[sum] : state[sum];
x++;
y += state[x];
}
+ r->x = x; r->y = y;
}