/*
 * Copyright (C) 2015 Square, 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.
 */
package keywhiz.hkdf;

/**
 * Representation for HKDF-supported HMAC functions.
 */
public enum Hash {
  SHA256("HmacSHA256", 32),
  SHA1("HmacSHA1", 20);
  // MD5 intentionally omitted

  private final String algorithm;
  private final int byteLength;

  Hash(String algorithm, int byteLength) {
    if (byteLength <= 0) {
      throw new IllegalArgumentException("byteLength must be positive");
    }
    this.algorithm = algorithm;
    this.byteLength = byteLength;
  }

  /**
   * @return JCA-recognized algorithm name.
   */
  public String getAlgorithm() {
    return algorithm;
  }

  /**
   * @return length of HMAC output in bytes.
   */
  public int getByteLength() {
    return byteLength;
  }
}