| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "crypto/aead.h" |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <string> |
| |
| #include "base/strings/string_util.h" |
| #include "crypto/openssl_util.h" |
| #include "third_party/boringssl/src/include/openssl/aes.h" |
| #include "third_party/boringssl/src/include/openssl/evp.h" |
| |
| namespace crypto { |
| |
| Aead::Aead(AeadAlgorithm algorithm) : key_(nullptr) { |
| EnsureOpenSSLInit(); |
| switch (algorithm) { |
| case AES_128_CTR_HMAC_SHA256: |
| aead_ = EVP_aead_aes_128_ctr_hmac_sha256(); |
| break; |
| } |
| } |
| |
| Aead::~Aead() { |
| } |
| |
| void Aead::Init(const std::string* key) { |
| DCHECK(!key_); |
| DCHECK_EQ(KeyLength(), key->size()); |
| key_ = key; |
| } |
| |
| bool Aead::Seal(const base::StringPiece& plaintext, |
| const base::StringPiece& nonce, |
| const base::StringPiece& additional_data, |
| std::string* ciphertext) const { |
| DCHECK(key_); |
| DCHECK_EQ(NonceLength(), nonce.size()); |
| EVP_AEAD_CTX ctx; |
| |
| if (!EVP_AEAD_CTX_init(&ctx, aead_, |
| reinterpret_cast<const uint8_t*>(key_->data()), |
| key_->size(), EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr)) { |
| return false; |
| } |
| |
| std::string result; |
| const size_t max_output_length = |
| EVP_AEAD_max_overhead(aead_) + plaintext.size(); |
| size_t output_length; |
| uint8_t* out_ptr = reinterpret_cast<uint8_t*>( |
| base::WriteInto(&result, max_output_length + 1)); |
| |
| if (!EVP_AEAD_CTX_seal( |
| &ctx, out_ptr, &output_length, max_output_length, |
| reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(), |
| reinterpret_cast<const uint8_t*>(plaintext.data()), plaintext.size(), |
| reinterpret_cast<const uint8_t*>(additional_data.data()), |
| additional_data.size())) { |
| EVP_AEAD_CTX_cleanup(&ctx); |
| return false; |
| } |
| |
| DCHECK_LE(output_length, max_output_length); |
| result.resize(output_length); |
| |
| ciphertext->swap(result); |
| EVP_AEAD_CTX_cleanup(&ctx); |
| |
| return true; |
| } |
| |
| bool Aead::Open(const base::StringPiece& ciphertext, |
| const base::StringPiece& nonce, |
| const base::StringPiece& additional_data, |
| std::string* plaintext) const { |
| DCHECK(key_); |
| EVP_AEAD_CTX ctx; |
| |
| if (!EVP_AEAD_CTX_init(&ctx, aead_, |
| reinterpret_cast<const uint8_t*>(key_->data()), |
| key_->size(), EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr)) { |
| return false; |
| } |
| |
| std::string result; |
| const size_t max_output_length = ciphertext.size(); |
| size_t output_length; |
| uint8_t* out_ptr = reinterpret_cast<uint8_t*>( |
| base::WriteInto(&result, max_output_length + 1)); |
| |
| if (!EVP_AEAD_CTX_open( |
| &ctx, out_ptr, &output_length, max_output_length, |
| reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(), |
| reinterpret_cast<const uint8_t*>(ciphertext.data()), |
| ciphertext.size(), |
| reinterpret_cast<const uint8_t*>(additional_data.data()), |
| additional_data.size())) { |
| EVP_AEAD_CTX_cleanup(&ctx); |
| return false; |
| } |
| |
| DCHECK_LE(output_length, max_output_length); |
| result.resize(output_length); |
| |
| plaintext->swap(result); |
| EVP_AEAD_CTX_cleanup(&ctx); |
| |
| return true; |
| } |
| |
| size_t Aead::KeyLength() const { |
| return EVP_AEAD_key_length(aead_); |
| } |
| |
| size_t Aead::NonceLength() const { |
| return EVP_AEAD_nonce_length(aead_); |
| } |
| |
| } // namespace crypto |