cc/mac/mac_key.h

// Copyright 2022 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.
//
////////////////////////////////////////////////////////////////////////////////

#ifndef TINK_MAC_MAC_KEY_H_
#define TINK_MAC_MAC_KEY_H_

#include <string>

#include "absl/strings/string_view.h"
#include "tink/key.h"
#include "tink/mac/mac_parameters.h"
#include "tink/util/statusor.h"

namespace crypto {
namespace tink {

// Represents a function to compute/verify a message authentication code (MAC).
class MacKey : public Key {
 public:
  // Returns the bytes prefixed to every MAC tag generated by this key.
  //
  // In order to make key rotation more efficient, Tink allows every MAC key to
  // have an associated tag output prefix.  When verifying a tag, only keys with
  // a matching prefix have to be tried.
  //
  // See https://developers.google.com/tink/wire-format#tink_output_prefix for
  // more background information on Tink output prefixes.
  virtual absl::string_view GetOutputPrefix() const = 0;

  const MacParameters& GetParameters() const override = 0;

  bool operator==(const Key& other) const override = 0;
};

}  // namespace tink
}  // namespace crypto


#endif  // TINK_MAC_MAC_KEY_H_