add srtp

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@1086 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/srtp/crypto/include/prng.h

@@ -0,0 +1,54 @@
+/*
+ * prng.h
+ *
+ * pseudorandom source
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+#ifndef PRNG_H
+#define PRNG_H
+
+#include "rand_source.h"  /* for rand_source_func_t definition       */
+#include "aes.h"          /* for aes                                 */
+#include "aes_icm.h"      /* for aes ctr                             */
+
+#define MAX_PRNG_OUT_LEN 0xffffffffU
+
+/*
+ * x917_prng is an ANSI X9.17-like AES-based PRNG
+ */
+
+typedef struct {
+  v128_t   state;          /* state data                              */
+  aes_expanded_key_t key;  /* secret key                              */
+  uint32_t octet_count;    /* number of octets output since last init */
+  rand_source_func_t rand; /* random source for re-initialization     */
+} x917_prng_t;
+
+err_status_t
+x917_prng_init(rand_source_func_t random_source);
+
+err_status_t
+x917_prng_get_octet_string(uint8_t *dest, uint32_t len);
+
+
+/*
+ * ctr_prng is an AES-CTR based PRNG
+ */
+
+typedef struct {
+  uint32_t octet_count;    /* number of octets output since last init */
+  aes_icm_ctx_t   state;   /* state data                              */
+  rand_source_func_t rand; /* random source for re-initialization     */
+} ctr_prng_t;
+
+err_status_t
+ctr_prng_init(rand_source_func_t random_source);
+
+err_status_t
+ctr_prng_get_octet_string(void *dest, uint32_t len);
+
+
+#endif