std::string decrypt_aes256(const std::string& cipher,const std::string& key,const std::string& iv)
{
std::string plain;
plain.resize((cipher.size()/AES_BLOCK_SIZE+1)*AES_BLOCK_SIZE);
EVP_CIPHER_CTX* ctx=nullptr;
try
{
std::string error_str="Decryption failed.";
ctx=EVP_CIPHER_CTX_new();
if(key.size()!=AES256_KEY_SIZE)
throw std::runtime_error(error_str);
int temp_length;
int temp_unaligned_length;
if(ctx==nullptr)
throw std::runtime_error(error_str);
if(EVP_CIPHER_CTX_set_padding(ctx,1)==0)
throw std::runtime_error(error_str);
if(EVP_DecryptInit(ctx,EVP_aes_256_cbc(),(uint8_t*)key.data(),(uint8_t*)iv.data())==0)
throw std::runtime_error(error_str);
if(EVP_DecryptUpdate(ctx,(uint8_t*)plain.data(),&temp_length,(uint8_t*)cipher.data(),cipher.size())==0)
throw std::runtime_error(error_str);
if(EVP_DecryptFinal(ctx,(uint8_t*)plain.data()+temp_length,&temp_unaligned_length)==0)
throw std::runtime_error(error_str);
plain.resize(temp_length+temp_unaligned_length);
}
catch(...)
{
aes_cleanup(ctx);
throw;
}
aes_cleanup(ctx);
return plain;
}
std::string encrypt_aes256(const std::string& plain,const std::string& key,const std::string& iv)
{
std::string cipher;
cipher.resize((plain.size()/AES_BLOCK_SIZE+1)*AES_BLOCK_SIZE);
EVP_CIPHER_CTX* ctx=nullptr;
try
{
ctx=EVP_CIPHER_CTX_new();
if(key.size()!=AES256_KEY_SIZE)
throw std::runtime_error("encrypt_aes256() - Given key size is invalid ("+
std::to_string(AES256_KEY_SIZE)+"bytes ).");
int temp_length;
int temp_unaligned_length;
if(ctx==nullptr)
throw std::runtime_error("encrypt_aes256() - Creating a EVP_CIPHER_CTX failed.");
if(EVP_CIPHER_CTX_set_padding(ctx,1)==0)
throw std::runtime_error("encrypt_aes256() - EVP_CIPHER_CTX_set_padding failed.");
if(EVP_EncryptInit(ctx,EVP_aes_256_cbc(),(uint8_t*)key.data(),(uint8_t*)iv.data())==0)
throw std::runtime_error("encrypt_aes256() - EVP_EncryptInit failed.");
if(EVP_EncryptUpdate(ctx,(uint8_t*)cipher.data(),&temp_length,(uint8_t*)plain.data(),plain.size())==0)
throw std::runtime_error("encrypt_aes256() - EVP_EncryptUpdate failed.");
if(EVP_EncryptFinal(ctx,(uint8_t*)cipher.data()+temp_length,&temp_unaligned_length)==0)
throw std::runtime_error("encrypt_aes256() - EVP_EncryptFinal failed.");
cipher.resize(temp_length+temp_unaligned_length);
}
catch(...)
{
aes_cleanup(ctx);
throw;
}
aes_cleanup(ctx);
return cipher;
}
void
cleanup_crypto(crypto_ctx_t *cctx)
{
aes_cleanup(cctx->crypto_ctx);
memset(cctx->salt, 0, 32);
free(cctx->salt);
free(cctx);
}