| // Copyright 2020 Google LLC |
| // |
| // 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 |
| // |
| // https://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 "third_party/private_membership/src/internal/aes_ctr_256_with_fixed_iv.h" |
| |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| #include <openssl/err.h> |
| #include <openssl/evp.h> |
| |
| namespace private_membership { |
| |
| namespace { |
| |
| absl::string_view EnsureNotNull(absl::string_view str) { |
| if (str.empty() && str.data() == nullptr) { |
| return absl::string_view(""); |
| } |
| return str; |
| } |
| |
| } // namespace |
| |
| ::rlwe::StatusOr<std::unique_ptr<AesCtr256WithFixedIV>> |
| AesCtr256WithFixedIV::Create(absl::string_view key) { |
| if (key.size() != kKeySize) { |
| return absl::InvalidArgumentError("Key size is invalid."); |
| } |
| return absl::WrapUnique<AesCtr256WithFixedIV>(new AesCtr256WithFixedIV(key)); |
| } |
| |
| AesCtr256WithFixedIV::AesCtr256WithFixedIV(absl::string_view key) |
| : key_(EnsureNotNull(key)), iv_(kIVSize, 0) {} |
| |
| ::rlwe::StatusOr<std::string> AesCtr256WithFixedIV::Encrypt( |
| absl::string_view plaintext) const { |
| plaintext = EnsureNotNull(plaintext); |
| |
| bssl::UniquePtr<EVP_CIPHER_CTX> ctx(EVP_CIPHER_CTX_new()); |
| if (ctx.get() == nullptr) { |
| return absl::InternalError("Could not initialize EVP_CIPHER_CTX."); |
| } |
| |
| int ret = EVP_EncryptInit_ex(ctx.get(), EVP_aes_256_ctr(), |
| /*impl=*/nullptr, |
| reinterpret_cast<const uint8_t*>(key_.data()), |
| reinterpret_cast<const uint8_t*>(iv_.data())); |
| if (ret != 1) { |
| return absl::InternalError("Could not initialize encryption."); |
| } |
| |
| // Allocates 1 byte more than necessary because it may potentially access |
| // &ciphertext[plaintext.size()] causing vector range check error. |
| std::vector<uint8_t> ciphertext(plaintext.size() + 1); |
| int len; |
| ret = EVP_EncryptUpdate(ctx.get(), &ciphertext[0], &len, |
| reinterpret_cast<const uint8_t*>(plaintext.data()), |
| plaintext.size()); |
| if (ret != 1) { |
| return absl::InternalError("Encryption failed."); |
| } |
| |
| if (len != plaintext.size()) { |
| return absl::InternalError("Ciphertext is incorrect size."); |
| } |
| return std::string(reinterpret_cast<const char*>(&ciphertext[0]), |
| plaintext.size()); |
| } |
| |
| ::rlwe::StatusOr<std::string> AesCtr256WithFixedIV::Decrypt( |
| absl::string_view ciphertext) const { |
| if (ciphertext.data() == nullptr) { |
| return absl::InternalError("Invalid null ciphertext."); |
| } |
| |
| bssl::UniquePtr<EVP_CIPHER_CTX> ctx(EVP_CIPHER_CTX_new()); |
| if (ctx.get() == nullptr) { |
| return absl::InternalError("Could not initialize EVP_CIPHER_CTX."); |
| } |
| |
| int ret = EVP_DecryptInit_ex(ctx.get(), EVP_aes_256_ctr(), |
| /*impl=*/nullptr, |
| reinterpret_cast<const uint8_t*>(key_.data()), |
| reinterpret_cast<const uint8_t*>(iv_.data())); |
| if (ret != 1) { |
| return absl::InternalError("Could not initialize decryption."); |
| } |
| |
| // Allocates 1 byte more than necessary because it may potentially access |
| // &plaintext[ciphertext.size()] causing vector range check error. |
| std::vector<uint8_t> plaintext(ciphertext.size() + 1); |
| int len; |
| ret = EVP_DecryptUpdate(ctx.get(), &plaintext[0], &len, |
| reinterpret_cast<const uint8_t*>(ciphertext.data()), |
| ciphertext.size()); |
| if (ret != 1) { |
| return absl::InternalError("Decryption failed."); |
| } |
| |
| if (len != ciphertext.size()) { |
| return absl::InternalError("Plaintext is incorrect size."); |
| } |
| return std::string(reinterpret_cast<const char*>(&plaintext[0]), |
| ciphertext.size()); |
| } |
| |
| } // namespace private_membership |