1 files changed, 98 insertions, 0 deletions
diff --git a/example/signmsg/src/prng.c b/example/signmsg/src/prng.c
new file mode 100644
index 0000000..129b859
--- /dev/null
+++ b/example/signmsg/src/prng.c
@@ -0,0 +1,98 @@
+/*############################################################################
+  # Copyright 2016-2017 Intel Corporation
+  #
+  # Licensed under the Apache License, Version 2.0 (the "License");
+  # you may not use this file except in compliance with the License.
+  # You may obtain a copy of the License at
+  #
+  #     http://www.apache.org/licenses/LICENSE-2.0
+  #
+  # Unless required by applicable law or agreed to in writing, software
+  # distributed under the License is distributed on an "AS IS" BASIS,
+  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  # See the License for the specific language governing permissions and
+  # limitations under the License.
+  ############################################################################*/
+
+/*!
+ * \file
+ * \brief Pseudo random number generator implementation.
+ */
+#include <ippcp.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "src/prng.h"
+
+EpidStatus PrngCreate(void** prng) {
+  // Security note:
+  // Random number generator used in the samples not claimed to be a
+  // cryptographically secure pseudo-random number generator.
+  EpidStatus sts = kEpidErr;
+  int prng_ctx_size = 0;
+  IppsPRNGState* prng_ctx = NULL;
+  int seed_ctx_size = 0;
+  IppsBigNumState* seed_ctx = NULL;
+  time_t seed_value;
+
+  if (!prng) return kEpidBadArgErr;
+
+  if (ippStsNoErr != ippsPRNGGetSize(&prng_ctx_size)) return kEpidErr;
+  if (ippStsNoErr !=
+      ippsBigNumGetSize((sizeof(seed_value) + 3) / 4, &seed_ctx_size))
+    return kEpidErr;
+
+  do {
+    prng_ctx = (IppsPRNGState*)calloc(1, prng_ctx_size);
+
+    if (!prng_ctx) {
+      sts = kEpidNoMemErr;
+      break;
+    }
+    if (ippStsNoErr != ippsPRNGInit(sizeof(seed_value) * 8, prng_ctx)) {
+      sts = kEpidErr;
+      break;
+    }
+
+    // seed PRNG
+    seed_ctx = (IppsBigNumState*)calloc(1, seed_ctx_size);
+    if (!seed_ctx) {
+      sts = kEpidNoMemErr;
+      break;
+    }
+    if (ippStsNoErr != ippsBigNumInit((sizeof(seed_value) + 3) / 4, seed_ctx)) {
+      sts = kEpidErr;
+      break;
+    }
+    time(&seed_value);
+    if (ippStsNoErr !=
+        ippsSetOctString_BN((void*)&seed_value, sizeof(seed_value), seed_ctx)) {
+      sts = kEpidErr;
+      break;
+    }
+    if (ippStsNoErr != ippsPRNGSetSeed(seed_ctx, prng_ctx)) {
+      sts = kEpidErr;
+      break;
+    }
+
+    *prng = prng_ctx;
+    prng_ctx = NULL;
+    sts = kEpidNoErr;
+  } while (0);
+
+  if (seed_ctx) free(seed_ctx);
+  if (prng_ctx) free(prng_ctx);
+  return sts;
+}
+
+void PrngDelete(void** prng) {
+  if (prng && *prng) {
+    free(*prng);
+    *prng = NULL;
+  }
+}
+
+// simple wrapper to hide IPP implementation.
+int __STDCALL PrngGen(unsigned int* rand_data, int num_bits, void* user_data) {
+  return ippsPRNGen(rand_data, num_bits, (IppsPRNGState*)user_data);
+}