text: /**
   * Copyright 2018 Google Inc.
   *
   * 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.
   *
   **************************************************************************
   */
  
  #import <Foundation/Foundation.h>
  
  #import "TINKKeyTemplate.h"
  
  typedef NS_ENUM(NSInteger, TINKMacKeyTemplates) {
    /**
     * HmacKey with the following parameters:
     *   - key size: 32 bytes
     *   - tag size: 16 bytes
     *   - hash function: SHA256
     *   - OutputPrefixType: TINK
     */
    TINKHmacSha256HalfSizeTag = 1,
  
    /**
     * HmacKey with the following parameters:
     *   - key size: 32 bytes
     *   - tag size: 32 bytes
     *   - hash function: SHA256
     *   - OutputPrefixType: TINK
     */
    TINKHmacSha256 = 2,
  
    /**
     * HmacKey with the following parameters:
     *   - key size: 64 bytes
     *   - tag size: 32 bytes
     *   - hash function: SHA512
     *   - OutputPrefixType: TINK
     */
    TINKHmacSha512HalfSizeTag = 3,
  
    /**
     * HmacKey with the following parameters:
     *   - key size: 64 bytes
     *   - tag size: 64 bytes
     *   - hash function: SHA512
     *   - OutputPrefixType: TINK
     */
    TINKHmacSha512 = 4,
  };
  
  NS_ASSUME_NONNULL_BEGIN
  
  /**
   * Pre-generated key templates for TINKMac key types.
   * One can use these templates to generate new TINKKeysetHandle object with fresh keys.
   *
   * Example:
   *
   * NSError *error = nil;
   * TINKMacConfig *macConfig = [[TINMacConfig alloc] initWithError:&error];
   * if (!macConfig || error) {
   *   // handle error.
   * }
   *
   * if (![TINKConfig registerConfig:macConfig error:&error]) {
   *   // handle error.
   * }
   *
   * TINKMacKeyTemplate *template =
   *    [TINMacKeyTemplate initWithKeyTemplate:TINKHmacSha256
   *                                     error:&error];
   * if (!template || error) {
   *   // handle error.
   * }
   *
   * TINKKeysetHandle *handle = [[TINKKeysetHandle alloc] initWithKeyTemplate:template
   *                                                                    error:&error];
   * if (!handle || error) {
   *   // handle error.
   * }
   *
   */
  @interface TINKMacKeyTemplate : TINKKeyTemplate
  
  - (nullable instancetype)init
      __attribute__((unavailable("Use -initWithKeyTemplate:error: instead.")));
  
  /**
   * Creates a TINKMacKeyTemplate that can be used to generate mac keysets.
   *
   * @param keyTemplate The mac key template to use.
   * @param error       If non-nil it will be populated with a descriptive error when the operation
   *                    fails.
   * @return            A TINKMacKeyTemplate or nil in case of error.
   */
  - (nullable instancetype)initWithKeyTemplate:(TINKMacKeyTemplates)keyTemplate
                                         error:(NSError **)error NS_DESIGNATED_INITIALIZER;
  
  @end
  
  NS_ASSUME_NONNULL_END
  