| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * 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 android.security; |
| |
| import java.security.NoSuchAlgorithmException; |
| |
| /** |
| * Base class for producing a message digest from different hash encryptions. |
| */ |
| public abstract class MessageDigest |
| { |
| /** |
| * Returns a digest object of the specified type. |
| * |
| * @param algorithm The type of hash function to use. Valid values are |
| * <em>SHA-1</em> and <em>MD5</em>. |
| * @return The respective MessageDigest object. Either a |
| * {@link android.security.Sha1MessageDigest} or |
| * {@link android.security.Md5MessageDigest} object. |
| * @throws NoSuchAlgorithmException If an invalid <var>algorithm</var> |
| * is given. |
| */ |
| public static MessageDigest getInstance(String algorithm) |
| throws NoSuchAlgorithmException |
| { |
| if (algorithm == null) { |
| return null; |
| } |
| |
| if (algorithm.equals("SHA-1")) { |
| return new Sha1MessageDigest(); |
| } |
| else if (algorithm.equals("MD5")) { |
| return new Md5MessageDigest(); |
| } |
| |
| throw new NoSuchAlgorithmException(); |
| } |
| |
| public abstract void update(byte[] input); |
| public abstract byte[] digest(); |
| |
| /** |
| * Produces a message digest for the given input. |
| * |
| * @param input The message to encrypt. |
| * @return The digest (hash sum). |
| */ |
| public abstract byte[] digest(byte[] input); |
| } |