add encryption (#1002)

* add encryption

* add doc

* add doc

* fix bug

fastdeploy/encryption/util/src/crypto/sha256_utils.cc

@@ -0,0 +1,85 @@
+// Copyright (c) 2021 PaddlePaddle Authors. 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 <stdio.h>
+#include <openssl/sha.h>
+#include <iomanip>
+#include <sstream>
+
+#include "fastdeploy/encryption/util/include/crypto/sha256_utils.h"
+namespace fastdeploy {
+namespace util {
+namespace crypto {
+
+void SHA256Utils::sha256(const void* data, size_t len, unsigned char* md) {
+  SHA256_CTX sha_ctx = {};
+  SHA256_Init(&sha_ctx);
+  SHA256_Update(&sha_ctx, data, len);
+  SHA256_Final(md, &sha_ctx);
+}
+std::vector<unsigned char> SHA256Utils::sha256(const void* data, size_t len) {
+  std::vector<unsigned char> md(32);
+  sha256(data, len, &md[0]);
+  return md;
+}
+std::vector<unsigned char> SHA256Utils::sha256(
+    const std::vector<unsigned char>& data) {
+  return sha256(&data[0], data.size());
+}
+std::string SHA256Utils::sha256_string(const void* data, size_t len) {
+  std::vector<unsigned char> md = sha256(data, len);
+  std::ostringstream oss;
+  oss << std::hex << std::setfill('0');
+  for (unsigned char c : md) {
+    oss << std::setw(2) << int(c);
+  }
+  return oss.str();
+}
+std::string SHA256Utils::sha256_string(const std::vector<unsigned char>& data) {
+  return sha256_string(&data[0], data.size());
+}
+std::string SHA256Utils::sha256_string(const std::string& string) {
+  return sha256_string(string.c_str(), string.size());
+}
+std::string SHA256Utils::sha256_file(const std::string& path) {
+  FILE* file = fopen(path.c_str(), "rb");
+  if (!file) {
+    return "";
+  }
+  unsigned char hash[SHA256_DIGEST_LENGTH];
+  SHA256_CTX sha_ctx = {};
+  SHA256_Init(&sha_ctx);
+  const int size = 32768;
+  void* buffer = malloc(size);
+  if (!buffer) {
+    fclose(file);
+    return "";
+  }
+  int read = 0;
+  while ((read = fread(buffer, 1, size, file))) {
+    SHA256_Update(&sha_ctx, buffer, read);
+  }
+  SHA256_Final(hash, &sha_ctx);
+  std::ostringstream oss;
+  oss << std::hex << std::setfill('0');
+  for (unsigned char c : hash) {
+    oss << std::setw(2) << int(c);
+  }
+  fclose(file);
+  free(buffer);
+  return oss.str();
+}
+
+}  // namespace crypto
+}  // namespace util
+}  // namespace fastdeploy