| // 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 |
| // |
| // 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 "tink/aead/cord_aead_wrapper.h" |
| |
| #include <memory> |
| #include <string> |
| #include <utility> |
| |
| #include "absl/status/status.h" |
| #include "absl/strings/cord.h" |
| #include "tink/aead/cord_aead.h" |
| #include "tink/crypto_format.h" |
| #include "tink/primitive_set.h" |
| #include "tink/util/status.h" |
| #include "tink/util/statusor.h" |
| |
| namespace crypto { |
| namespace tink { |
| |
| namespace { |
| |
| util::Status Validate(PrimitiveSet<CordAead>* aead_set) { |
| if (aead_set == nullptr) { |
| return util::Status(absl::StatusCode::kInternal, |
| "aead_set must be non-NULL"); |
| } |
| if (aead_set->get_primary() == nullptr) { |
| return util::Status(absl::StatusCode::kInvalidArgument, |
| "aead_set has no primary"); |
| } |
| return util::OkStatus(); |
| } |
| |
| class CordAeadSetWrapper : public CordAead { |
| public: |
| explicit CordAeadSetWrapper(std::unique_ptr<PrimitiveSet<CordAead>> aead_set) |
| : aead_set_(std::move(aead_set)) {} |
| |
| crypto::tink::util::StatusOr<absl::Cord> Encrypt( |
| absl::Cord plaintext, absl::Cord associated_data) const override; |
| |
| crypto::tink::util::StatusOr<absl::Cord> Decrypt( |
| absl::Cord ciphertext, absl::Cord associated_data) const override; |
| |
| ~CordAeadSetWrapper() override {} |
| |
| private: |
| std::unique_ptr<PrimitiveSet<CordAead>> aead_set_; |
| }; |
| |
| util::StatusOr<absl::Cord> CordAeadSetWrapper::Encrypt( |
| absl::Cord plaintext, absl::Cord associated_data) const { |
| auto encrypt_result = aead_set_->get_primary()->get_primitive().Encrypt( |
| plaintext, associated_data); |
| if (!encrypt_result.ok()) return encrypt_result.status(); |
| absl::Cord result; |
| result.Append(aead_set_->get_primary()->get_identifier()); |
| result.Append(encrypt_result.value()); |
| return result; |
| } |
| |
| util::StatusOr<absl::Cord> CordAeadSetWrapper::Decrypt( |
| absl::Cord ciphertext, absl::Cord associated_data) const { |
| if (ciphertext.size() > CryptoFormat::kNonRawPrefixSize) { |
| std::string key_id = |
| std::string(ciphertext.Subcord(0, CryptoFormat::kNonRawPrefixSize)); |
| auto primitives_result = aead_set_->get_primitives(key_id); |
| if (primitives_result.ok()) { |
| auto raw_ciphertext = |
| ciphertext.Subcord(key_id.size(), ciphertext.size()); |
| for (auto& aead_entry : *(primitives_result.value())) { |
| CordAead& aead = aead_entry->get_primitive(); |
| auto decrypt_result = aead.Decrypt(raw_ciphertext, associated_data); |
| if (decrypt_result.ok()) { |
| return std::move(decrypt_result.value()); |
| } else { |
| // LOG that a matching key didn't decrypt the ciphertext. |
| } |
| } |
| } |
| } |
| |
| // No matching key succeeded with decryption, try all RAW keys. |
| auto raw_primitives_result = aead_set_->get_raw_primitives(); |
| if (raw_primitives_result.ok()) { |
| for (auto& aead_entry : *(raw_primitives_result.value())) { |
| CordAead& aead = aead_entry->get_primitive(); |
| auto decrypt_result = aead.Decrypt(ciphertext, associated_data); |
| if (decrypt_result.ok()) { |
| return std::move(decrypt_result.value()); |
| } |
| } |
| } |
| return util::Status(absl::StatusCode::kInvalidArgument, "decryption failed"); |
| } |
| } // anonymous namespace |
| |
| util::StatusOr<std::unique_ptr<CordAead>> CordAeadWrapper::Wrap( |
| std::unique_ptr<PrimitiveSet<CordAead>> aead_set) const { |
| util::Status status = Validate(aead_set.get()); |
| if (!status.ok()) return status; |
| std::unique_ptr<CordAead> aead(new CordAeadSetWrapper(std::move(aead_set))); |
| return std::move(aead); |
| } |
| |
| } // namespace tink |
| } // namespace crypto |