1 files changed, 119 insertions, 0 deletions
diff --git a/client/cpp/openssl_hash_impl.cc b/client/cpp/openssl_hash_impl.cc
new file mode 100644
index 0000000..82993d8
--- /dev/null
+++ b/client/cpp/openssl_hash_impl.cc
@@ -0,0 +1,119 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// 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.
+
+#include "openssl_hash_impl.h"
+
+#include <stdlib.h>
+#include <string>
+
+#include <openssl/evp.h>  // EVP_sha256
+#include <openssl/hmac.h>  // HMAC
+#include <openssl/md5.h>  // MD5
+#include <openssl/sha.h>  // SHA256_DIGEST_LENGTH
+
+namespace rappor {
+
+// of type HmacFunc in rappor_deps.h
+bool HmacSha256(const std::string& key, const std::string& value,
+          std::vector<uint8_t>* output) {
+  output->resize(SHA256_DIGEST_LENGTH, 0);
+
+  // Returns a pointer on success, or NULL on failure.
+  unsigned char* result = HMAC(
+      EVP_sha256(), key.c_str(), key.size(),
+      // std::string has 'char', OpenSSL wants unsigned char.
+      reinterpret_cast<const unsigned char*>(value.c_str()),
+      value.size(),
+      output->data(),
+      NULL);
+
+  return (result != NULL);
+}
+
+// Of type HmacFunc in rappor_deps.h
+//
+// The length of the passed-in output vector determines how many
+// bytes are returned.
+//
+// No reseed operation, but recommended reseed_interval <= 2^48 updates.
+// Since we're seeding for each value and typically don't need
+// so many bytes, we should be OK.
+bool HmacDrbg(const std::string& key, const std::string& value,
+              std::vector<uint8_t>* output) {
+  const unsigned char k_array[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+  };
+  std::string v;
+  std::vector<uint8_t> temp_output;
+  int num_bytes = output->size();
+  if (num_bytes == 0) {
+    // By default return 32 bytes for Uint32 applications.
+    num_bytes = 32;
+  }
+
+  v.append(32u, 0x01);
+  temp_output.resize(32, 0);
+
+  std::string temp_str(v);
+  temp_str.append(std::string("\0", 1));
+  // provided_data is key|value.
+  temp_str.append(key);
+  temp_str.append(value);
+
+  output->resize(0);
+
+  // Instantiate.
+  if (!HmacSha256(std::string(k_array, k_array + 32), temp_str, &temp_output)) {
+    return false;
+  }
+  std::string k(temp_output.begin(), temp_output.end());
+  if (!HmacSha256(k, v, &temp_output)) {
+    return false;
+  }
+  v = std::string(temp_output.begin(), temp_output.end());
+  if (!HmacSha256(k, v + std::string("\1", 1) + key + value, &temp_output)) {
+    return false;
+  }
+  k = std::string(temp_output.begin(), temp_output.end());
+  if (!HmacSha256(k, v, &temp_output)) {
+    return false;
+  }
+  v = std::string(temp_output.begin(), temp_output.end());
+
+  while (output->size() < num_bytes) {
+    // Generate.
+    if (!HmacSha256(k, v, &temp_output)) {
+      return false;
+    }
+    v = std::string(temp_output.begin(), temp_output.end());
+    output->insert(output->end(), temp_output.begin(), temp_output.end());
+  }
+  output->resize(num_bytes);
+  return true;
+}
+
+// of type HashFunc in rappor_deps.h
+bool Md5(const std::string& value, std::vector<uint8_t>* output) {
+  output->resize(MD5_DIGEST_LENGTH, 0);
+
+  // std::string has 'char', OpenSSL wants unsigned char.
+  MD5(reinterpret_cast<const unsigned char*>(value.c_str()),
+      value.size(), output->data());
+  return true;  // OpenSSL MD5 doesn't return an error code
+}
+
+}  // namespace rappor