text: // Copyright 2021 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_JWT_JWT_MAC_H_
  #define TINK_JWT_JWT_MAC_H_
  
  #include <string>
  
  #include "absl/strings/string_view.h"
  #include "tink/jwt/jwt_validator.h"
  #include "tink/jwt/raw_jwt.h"
  #include "tink/jwt/verified_jwt.h"
  #include "tink/util/status.h"
  #include "tink/util/statusor.h"
  
  namespace crypto {
  namespace tink {
  
  ///////////////////////////////////////////////////////////////////////////////
  // Interface for authenticating and verifying JWT with JWS MAC.
  //
  // Sees RFC 7519 and RFC 7515. Security guarantees: similar to MAC.
  class JwtMac {
   public:
    // Computes a MAC and encodes the raw JWT token and the MAC in the JWS compact
    // serialization format.
    virtual crypto::tink::util::StatusOr<std::string> ComputeMacAndEncode(
        const RawJwt& token) const = 0;
  
    // Verifies and decodes a JWT token in the JWS compact serialization format.
    //
    // The JWT is validated against the rules in validator. That is, every claim
    // in validator must also be present in the JWT. For example, if validator
    // contains an issuer (iss) claim, the JWT must contain an identical claim.
    // The JWT can contain claims that are NOT in the validator. However, if the
    // JWT contains a list of audiences, the validator must also contain an
    // audience in the list.
    //
    // If the JWT contains timestamp claims such as expiration (exp), issued_at
    // (iat) or not_before (nbf), they will also be validated. validator allows to
    // set a clock skew, to deal with small clock differences among different
    // machines.
    virtual crypto::tink::util::StatusOr<VerifiedJwt> VerifyMacAndDecode(
        absl::string_view compact, const JwtValidator& validator) const = 0;
  
    virtual ~JwtMac() {}
  };
  
  }  // namespace tink
  }  // namespace crypto
  
  #endif  // TINK_JWT_JWT_MAC_H_
  