diff --git a/mindspore/core/load_mindir/load_model.cc b/mindspore/core/load_mindir/load_model.cc
index ed3bdf65259..62574ee7db2 100644
--- a/mindspore/core/load_mindir/load_model.cc
+++ b/mindspore/core/load_mindir/load_model.cc
@@ -122,8 +122,8 @@ bool get_all_files(const std::string &dir_in, std::vector<std::string> *files) {
 
 int endsWith(string s, string sub) { return s.rfind(sub) == (s.length() - sub.length()) ? 1 : 0; }
 
-bool ParseModelProto(mind_ir::ModelProto *model, std::string path, const unsigned char *dec_key, const size_t key_len,
-                     const std::string &dec_mode) {
+bool ParseModelProto(mind_ir::ModelProto *model, const std::string &path, const unsigned char *dec_key,
+                     const size_t key_len, const std::string &dec_mode) {
   if (dec_key != nullptr) {
     size_t plain_len;
     auto plain_data = Decrypt(&plain_len, path, dec_key, key_len, dec_mode);
@@ -131,7 +131,7 @@ bool ParseModelProto(mind_ir::ModelProto *model, std::string path, const unsigne
       MS_LOG(ERROR) << "Decrypt MindIR file failed, please check the correctness of the dec_key or dec_mode.";
       return false;
     }
-    if (!model->ParseFromArray(reinterpret_cast<char *>(plain_data.get()), plain_len)) {
+    if (!model->ParseFromArray(reinterpret_cast<char *>(plain_data.get()), static_cast<int32_t>(plain_len))) {
       MS_LOG(ERROR) << "Load MindIR file failed, please check the correctness of the file, dec_key or dec_mode.";
       return false;
     }
@@ -145,8 +145,8 @@ bool ParseModelProto(mind_ir::ModelProto *model, std::string path, const unsigne
   return true;
 }
 
-bool ParseGraphProto(mind_ir::GraphProto *graph, std::string path, const unsigned char *dec_key, const size_t key_len,
-                     const std::string &dec_mode) {
+bool ParseGraphProto(mind_ir::GraphProto *graph, const std::string &path, const unsigned char *dec_key,
+                     const size_t key_len, const std::string &dec_mode) {
   if (dec_key != nullptr) {
     size_t plain_len;
     auto plain_data = Decrypt(&plain_len, path, dec_key, key_len, dec_mode);
@@ -154,7 +154,7 @@ bool ParseGraphProto(mind_ir::GraphProto *graph, std::string path, const unsigne
       MS_LOG(ERROR) << "Decrypt MindIR file failed, please check the correctness of the dec_key or dec_mode.";
       return false;
     }
-    if (!graph->ParseFromArray(reinterpret_cast<char *>(plain_data.get()), plain_len)) {
+    if (!graph->ParseFromArray(reinterpret_cast<char *>(plain_data.get()), static_cast<int32_t>(plain_len))) {
       MS_LOG(ERROR) << "Load variable file failed, please check the correctness of the mindir's variable file, "
                        "dec_key or dec_mode";
       return false;
diff --git a/mindspore/core/utils/crypto.cc b/mindspore/core/utils/crypto.cc
index 4a44080529f..4ea1e5aeffb 100644
--- a/mindspore/core/utils/crypto.cc
+++ b/mindspore/core/utils/crypto.cc
@@ -52,17 +52,18 @@ bool IsCipherFile(const std::string &file_path) {
     return false;
   }
   std::vector<char> int_buf(sizeof(int32_t));
-  fid.read(int_buf.data(), sizeof(int32_t));
+  fid.read(int_buf.data(), static_cast<int64_t>(sizeof(int32_t)));
   fid.close();
   auto flag = ByteToInt(reinterpret_cast<Byte *>(int_buf.data()), int_buf.size());
-  return flag == MAGIC_NUM;
+  return static_cast<unsigned int>(flag) == MAGIC_NUM;
 }
 
 bool IsCipherFile(const Byte *model_data) {
+  MS_EXCEPTION_IF_NULL(model_data);
   std::vector<Byte> int_buf;
   int_buf.assign(model_data, model_data + sizeof(int32_t));
   auto flag = ByteToInt(int_buf.data(), int_buf.size());
-  return flag == MAGIC_NUM;
+  return static_cast<unsigned int>(flag) == MAGIC_NUM;
 }
 #if defined(_WIN32)
 std::unique_ptr<Byte[]> Encrypt(size_t *encrypt_len, const Byte *plain_data, size_t plain_len, const Byte *key,
@@ -93,7 +94,9 @@ bool ParseEncryptData(const Byte *encrypt_data, size_t encrypt_len, std::vector<
 
   int_buf.assign(encrypt_data + iv_len + sizeof(int32_t), encrypt_data + iv_len + sizeof(int32_t) + sizeof(int32_t));
   auto cipher_len = ByteToInt(int_buf.data(), int_buf.size());
-  if (iv_len <= 0 || cipher_len <= 0 || ((iv_len + sizeof(int32_t) + cipher_len + sizeof(int32_t)) != encrypt_len)) {
+  if (iv_len <= 0 || cipher_len <= 0 ||
+      ((static_cast<size_t>(iv_len) + sizeof(int32_t) + static_cast<size_t>(cipher_len) + sizeof(int32_t)) !=
+       encrypt_len)) {
     MS_LOG(ERROR) << "Failed to parse encrypt data.";
     return false;
   }
@@ -108,11 +111,10 @@ bool ParseEncryptData(const Byte *encrypt_data, size_t encrypt_len, std::vector<
 bool ParseMode(const std::string &mode, std::string *alg_mode, std::string *work_mode) {
   std::smatch results;
   std::regex re("([A-Z]{3})-([A-Z]{3})");
-  if (!std::regex_match(mode.c_str(), re)) {
+  if (!(std::regex_match(mode.c_str(), re) && std::regex_search(mode, results, re))) {
     MS_LOG(ERROR) << "Mode " << mode << " is invalid.";
     return false;
   }
-  std::regex_search(mode, results, re);
   *alg_mode = results[1];
   *work_mode = results[2];
   return true;
@@ -171,7 +173,13 @@ EVP_CIPHER_CTX *GetEvpCipherCtx(const std::string &work_mode, const Byte *key, i
     MS_LOG(ERROR) << "EVP_EncryptInit_ex failed";
     return nullptr;
   }
-  if (work_mode == "CBC") EVP_CIPHER_CTX_set_padding(ctx, 1);
+  if (work_mode == "CBC") {
+    ret = EVP_CIPHER_CTX_set_padding(ctx, 1);
+    if (ret != 1) {
+      MS_LOG(ERROR) << "EVP_CIPHER_CTX_set_padding failed";
+      return nullptr;
+    }
+  }
   return ctx;
 }
 
@@ -181,7 +189,11 @@ bool BlockEncrypt(Byte *encrypt_data, size_t *encrypt_data_len, const std::vecto
   int32_t cipher_len = 0;
   int32_t iv_len = AES_BLOCK_SIZE;
   std::vector<Byte> iv(iv_len);
-  RAND_bytes(iv.data(), sizeof(Byte) * iv_len);
+  auto ret = RAND_bytes(iv.data(), iv_len);
+  if (ret != 1) {
+    MS_LOG(ERROR) << "RAND_bytes error, failed to init iv.";
+    return false;
+  }
   std::vector<Byte> iv_cpy(iv);
 
   std::string alg_mode;
@@ -197,23 +209,28 @@ bool BlockEncrypt(Byte *encrypt_data, size_t *encrypt_data_len, const std::vecto
   }
 
   std::vector<Byte> cipher_data_buf(plain_data.size() + AES_BLOCK_SIZE);
-  auto ret_evp = EVP_EncryptUpdate(ctx, cipher_data_buf.data(), &cipher_len, plain_data.data(), plain_data.size());
+  auto ret_evp = EVP_EncryptUpdate(ctx, cipher_data_buf.data(), &cipher_len, plain_data.data(),
+                                   static_cast<int32_t>(plain_data.size()));
   if (ret_evp != 1) {
     MS_LOG(ERROR) << "EVP_EncryptUpdate failed";
     return false;
   }
   if (work_mode == "CBC") {
     int32_t flen = 0;
-    EVP_EncryptFinal_ex(ctx, cipher_data_buf.data() + cipher_len, &flen);
+    ret_evp = EVP_EncryptFinal_ex(ctx, cipher_data_buf.data() + cipher_len, &flen);
+    if (ret_evp != 1) {
+      MS_LOG(ERROR) << "EVP_EncryptFinal_ex failed";
+      return false;
+    }
     cipher_len += flen;
   }
   EVP_CIPHER_CTX_free(ctx);
 
   size_t offset = 0;
   std::vector<Byte> int_buf(sizeof(int32_t));
-  *encrypt_data_len = sizeof(int32_t) + iv_len + sizeof(int32_t) + cipher_len;
-  IntToByte(&int_buf, *encrypt_data_len);
-  auto ret = memcpy_s(encrypt_data, encrypt_data_buf_len, int_buf.data(), int_buf.size());
+  *encrypt_data_len = sizeof(int32_t) + static_cast<size_t>(iv_len) + sizeof(int32_t) + static_cast<size_t>(cipher_len);
+  IntToByte(&int_buf, static_cast<int32_t>(*encrypt_data_len));
+  ret = memcpy_s(encrypt_data, encrypt_data_buf_len, int_buf.data(), int_buf.size());
   if (ret != 0) {
     MS_LOG(EXCEPTION) << "memcpy_s error, errorno " << ret;
   }
@@ -239,7 +256,8 @@ bool BlockEncrypt(Byte *encrypt_data, size_t *encrypt_data_len, const std::vecto
   }
   offset += int_buf.size();
 
-  ret = memcpy_s(encrypt_data + offset, encrypt_data_buf_len - offset, cipher_data_buf.data(), cipher_len);
+  ret = memcpy_s(encrypt_data + offset, encrypt_data_buf_len - offset, cipher_data_buf.data(),
+                 static_cast<size_t>(cipher_len));
   if (ret != 0) {
     MS_LOG(EXCEPTION) << "memcpy_s error, errorno " << ret;
   }
@@ -265,7 +283,8 @@ bool BlockDecrypt(Byte *plain_data, int32_t *plain_len, const Byte *encrypt_data
     MS_LOG(ERROR) << "Failed to get EVP_CIPHER_CTX.";
     return false;
   }
-  auto ret = EVP_DecryptUpdate(ctx, plain_data, plain_len, cipher_data.data(), cipher_data.size());
+  auto ret =
+    EVP_DecryptUpdate(ctx, plain_data, plain_len, cipher_data.data(), static_cast<int32_t>(cipher_data.size()));
   if (ret != 1) {
     MS_LOG(ERROR) << "EVP_DecryptUpdate failed";
     return false;
@@ -285,6 +304,9 @@ bool BlockDecrypt(Byte *plain_data, int32_t *plain_len, const Byte *encrypt_data
 
 std::unique_ptr<Byte[]> Encrypt(size_t *encrypt_len, const Byte *plain_data, size_t plain_len, const Byte *key,
                                 size_t key_len, const std::string &enc_mode) {
+  MS_EXCEPTION_IF_NULL(plain_data);
+  MS_EXCEPTION_IF_NULL(key);
+
   size_t block_enc_buf_len = MAX_BLOCK_SIZE + RESERVED_BYTE_PER_BLOCK;
   size_t encrypt_buf_len = plain_len + (plain_len + MAX_BLOCK_SIZE) / MAX_BLOCK_SIZE * RESERVED_BYTE_PER_BLOCK;
   std::vector<Byte> int_buf(sizeof(int32_t));
@@ -298,12 +320,12 @@ std::unique_ptr<Byte[]> Encrypt(size_t *encrypt_len, const Byte *plain_data, siz
     size_t block_enc_len = block_enc_buf.size();
     size_t cur_block_size = std::min(MAX_BLOCK_SIZE, plain_len - offset);
     block_buf.assign(plain_data + offset, plain_data + offset + cur_block_size);
-    if (!BlockEncrypt(block_enc_buf.data(), &block_enc_len, block_buf, key, key_len, enc_mode)) {
+    if (!BlockEncrypt(block_enc_buf.data(), &block_enc_len, block_buf, key, static_cast<int32_t>(key_len), enc_mode)) {
       MS_LOG(ERROR) << "Failed to encrypt data, please check if enc_key or enc_mode is valid.";
       return nullptr;
     }
 
-    IntToByte(&int_buf, MAGIC_NUM);
+    IntToByte(&int_buf, static_cast<int32_t>(MAGIC_NUM));
     size_t capacity = std::min(encrypt_buf_len - *encrypt_len, SECUREC_MEM_MAX_LEN);  // avoid dest size over 2gb
     auto ret = memcpy_s(encrypt_data.get() + *encrypt_len, capacity, int_buf.data(), sizeof(int32_t));
     if (ret != 0) {
@@ -324,13 +346,15 @@ std::unique_ptr<Byte[]> Encrypt(size_t *encrypt_len, const Byte *plain_data, siz
 
 std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const std::string &encrypt_data_path, const Byte *key,
                                 size_t key_len, const std::string &dec_mode) {
+  MS_EXCEPTION_IF_NULL(key);
+
   std::ifstream fid(encrypt_data_path, std::ios::in | std::ios::binary);
   if (!fid) {
     MS_LOG(ERROR) << "Open file '" << encrypt_data_path << "' failed, please check the correct of the file.";
     return nullptr;
   }
   fid.seekg(0, std::ios_base::end);
-  size_t file_size = fid.tellg();
+  size_t file_size = static_cast<size_t>(fid.tellg());
   fid.clear();
   fid.seekg(0);
 
@@ -342,26 +366,31 @@ std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const std::string &encrypt_
 
   *decrypt_len = 0;
   while (static_cast<size_t>(fid.tellg()) < file_size) {
-    fid.read(int_buf.data(), sizeof(int32_t));
+    fid.read(int_buf.data(), static_cast<int32_t>(sizeof(int32_t)));
     auto cipher_flag = ByteToInt(reinterpret_cast<Byte *>(int_buf.data()), int_buf.size());
-    if (cipher_flag != MAGIC_NUM) {
+    if (static_cast<unsigned int>(cipher_flag) != MAGIC_NUM) {
       MS_LOG(ERROR) << "File \"" << encrypt_data_path << "\" is not an encrypted file and cannot be decrypted";
       return nullptr;
     }
-    fid.read(int_buf.data(), sizeof(int32_t));
+    fid.read(int_buf.data(), static_cast<int64_t>(sizeof(int32_t)));
     auto block_size = ByteToInt(reinterpret_cast<Byte *>(int_buf.data()), int_buf.size());
-    fid.read(block_buf.data(), sizeof(char) * block_size);
+    if (block_size < 0) {
+      MS_LOG(ERROR) << "The block_size read from the cipher file must be not negative, but got " << block_size;
+      return nullptr;
+    }
+    fid.read(block_buf.data(), static_cast<int64_t>(block_size));
     if (!(BlockDecrypt(decrypt_block_buf.data(), &decrypt_block_len, reinterpret_cast<Byte *>(block_buf.data()),
-                       block_size, key, key_len, dec_mode))) {
+                       static_cast<size_t>(block_size), key, static_cast<int32_t>(key_len), dec_mode))) {
       MS_LOG(ERROR) << "Failed to decrypt data, please check if dec_key or dec_mode is valid";
       return nullptr;
     }
     size_t capacity = std::min(file_size - *decrypt_len, SECUREC_MEM_MAX_LEN);
-    auto ret = memcpy_s(decrypt_data.get() + *decrypt_len, capacity, decrypt_block_buf.data(), decrypt_block_len);
+    auto ret = memcpy_s(decrypt_data.get() + *decrypt_len, capacity, decrypt_block_buf.data(),
+                        static_cast<int32_t>(decrypt_block_len));
     if (ret != 0) {
       MS_LOG(EXCEPTION) << "memcpy_s error, errorno " << ret;
     }
-    *decrypt_len += decrypt_block_len;
+    *decrypt_len += static_cast<size_t>(decrypt_block_len);
   }
   fid.close();
   return decrypt_data;
@@ -369,6 +398,9 @@ std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const std::string &encrypt_
 
 std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const Byte *model_data, size_t data_size, const Byte *key,
                                 size_t key_len, const std::string &dec_mode) {
+  MS_EXCEPTION_IF_NULL(model_data);
+  MS_EXCEPTION_IF_NULL(key);
+
   std::vector<char> block_buf;
   std::vector<char> int_buf(sizeof(int32_t));
   std::vector<Byte> decrypt_block_buf(MAX_BLOCK_SIZE);
@@ -381,7 +413,7 @@ std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const Byte *model_data, siz
     int_buf.assign(model_data + offset, model_data + offset + sizeof(int32_t));
     offset += int_buf.size();
     auto cipher_flag = ByteToInt(reinterpret_cast<Byte *>(int_buf.data()), int_buf.size());
-    if (cipher_flag != MAGIC_NUM) {
+    if (static_cast<unsigned int>(cipher_flag) != MAGIC_NUM) {
       MS_LOG(ERROR) << "model_data is not encrypted and therefore cannot be decrypted.";
       return nullptr;
     }
@@ -389,19 +421,24 @@ std::unique_ptr<Byte[]> Decrypt(size_t *decrypt_len, const Byte *model_data, siz
     int_buf.assign(model_data + offset, model_data + offset + sizeof(int32_t));
     offset += int_buf.size();
     auto block_size = ByteToInt(reinterpret_cast<Byte *>(int_buf.data()), int_buf.size());
+    if (block_size < 0) {
+      MS_LOG(ERROR) << "The block_size read from the cipher data must be not negative, but got " << block_size;
+      return nullptr;
+    }
     block_buf.assign(model_data + offset, model_data + offset + block_size);
     offset += block_buf.size();
     if (!(BlockDecrypt(decrypt_block_buf.data(), &decrypt_block_len, reinterpret_cast<Byte *>(block_buf.data()),
-                       block_buf.size(), key, key_len, dec_mode))) {
+                       block_buf.size(), key, static_cast<int32_t>(key_len), dec_mode))) {
       MS_LOG(ERROR) << "Failed to decrypt data, please check if dec_key or dec_mode is valid";
       return nullptr;
     }
     size_t capacity = std::min(data_size - *decrypt_len, SECUREC_MEM_MAX_LEN);
-    auto ret = memcpy_s(decrypt_data.get() + *decrypt_len, capacity, decrypt_block_buf.data(), decrypt_block_len);
+    auto ret = memcpy_s(decrypt_data.get() + *decrypt_len, capacity, decrypt_block_buf.data(),
+                        static_cast<size_t>(decrypt_block_len));
     if (ret != 0) {
       MS_LOG(EXCEPTION) << "memcpy_s error, errorno " << ret;
     }
-    *decrypt_len += decrypt_block_len;
+    *decrypt_len += static_cast<size_t>(decrypt_block_len);
   }
   return decrypt_data;
 }
diff --git a/mindspore/lite/tools/converter/import/mindspore_importer.cc b/mindspore/lite/tools/converter/import/mindspore_importer.cc
index 01b5f6c68ab..bc06c8886a4 100644
--- a/mindspore/lite/tools/converter/import/mindspore_importer.cc
+++ b/mindspore/lite/tools/converter/import/mindspore_importer.cc
@@ -186,7 +186,10 @@ FuncGraphPtr MindsporeImporter::ImportMindIR(const converter::Flags &flag) {
       return nullptr;
     }
     func_graph = LoadMindIR(flag.modelFile, false, key, key_len, flag.dec_mode);
-    memset(key, 0, key_len);
+    auto ret = memset_s(key, sizeof(key), 0, key_len);
+    if (ret != 0) {
+      MS_LOG(EXCEPTION) << "memset_s error";
+    }
   } else {
     func_graph = LoadMindIR(flag.modelFile);
   }