1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef QUICHE_QUIC_CORE_CRYPTO_CRYPTO_SECRET_BOXER_H_ 6 #define QUICHE_QUIC_CORE_CRYPTO_CRYPTO_SECRET_BOXER_H_ 7 8 #include <cstddef> 9 #include <memory> 10 #include <string> 11 #include <vector> 12 13 #include "absl/strings/string_view.h" 14 #include "quiche/quic/core/crypto/quic_random.h" 15 #include "quiche/quic/platform/api/quic_export.h" 16 #include "quiche/quic/platform/api/quic_mutex.h" 17 18 namespace quic { 19 20 // CryptoSecretBoxer encrypts small chunks of plaintext (called 'boxing') and 21 // then, later, can authenticate+decrypt the resulting boxes. This object is 22 // thread-safe. 23 class QUICHE_EXPORT CryptoSecretBoxer { 24 public: 25 CryptoSecretBoxer(); 26 CryptoSecretBoxer(const CryptoSecretBoxer&) = delete; 27 CryptoSecretBoxer& operator=(const CryptoSecretBoxer&) = delete; 28 ~CryptoSecretBoxer(); 29 30 // GetKeySize returns the number of bytes in a key. 31 static size_t GetKeySize(); 32 33 // SetKeys sets a list of encryption keys. The first key in the list will be 34 // used by |Box|, but all supplied keys will be tried by |Unbox|, to handle 35 // key skew across the fleet. This must be called before |Box| or |Unbox|. 36 // Keys must be |GetKeySize()| bytes long. No change is made if any key is 37 // invalid, or if there are no keys supplied. 38 bool SetKeys(const std::vector<std::string>& keys); 39 40 // Box encrypts |plaintext| using a random nonce generated from |rand| and 41 // returns the resulting ciphertext. Since an authenticator and nonce are 42 // included, the result will be slightly larger than |plaintext|. The first 43 // key in the vector supplied to |SetKeys| will be used. |SetKeys| must be 44 // called before calling this method. 45 std::string Box(QuicRandom* rand, absl::string_view plaintext) const; 46 47 // Unbox takes the result of a previous call to |Box| in |ciphertext| and 48 // authenticates+decrypts it. If |ciphertext| cannot be decrypted with any of 49 // the supplied keys, the function returns false. Otherwise, |out_storage| is 50 // used to store the result and |out| is set to point into |out_storage| and 51 // contains the original plaintext. 52 bool Unbox(absl::string_view ciphertext, std::string* out_storage, 53 absl::string_view* out) const; 54 55 private: 56 struct State; 57 58 mutable QuicMutex lock_; 59 60 // state_ is an opaque pointer to whatever additional state the concrete 61 // implementation of CryptoSecretBoxer requires. 62 std::unique_ptr<State> state_ QUIC_GUARDED_BY(lock_); 63 }; 64 65 } // namespace quic 66 67 #endif // QUICHE_QUIC_CORE_CRYPTO_CRYPTO_SECRET_BOXER_H_ 68