65 lines
2.0 KiB
Java
65 lines
2.0 KiB
Java
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/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.security;
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import java.security.NoSuchAlgorithmException;
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/**
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* Base class for producing a message digest from different hash encryptions.
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*/
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public abstract class MessageDigest
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{
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/**
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* Returns a digest object of the specified type.
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*
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* @param algorithm The type of hash function to use. Valid values are
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* <em>SHA-1</em> and <em>MD5</em>.
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* @return The respective MessageDigest object. Either a
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* {@link android.security.Sha1MessageDigest} or
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* {@link android.security.Md5MessageDigest} object.
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* @throws NoSuchAlgorithmException If an invalid <var>algorithm</var>
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* is given.
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*/
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public static MessageDigest getInstance(String algorithm)
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throws NoSuchAlgorithmException
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{
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if (algorithm == null) {
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return null;
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}
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if (algorithm.equals("SHA-1")) {
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return new Sha1MessageDigest();
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}
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else if (algorithm.equals("MD5")) {
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return new Md5MessageDigest();
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}
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throw new NoSuchAlgorithmException();
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}
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public abstract void update(byte[] input);
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public abstract byte[] digest();
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/**
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* Produces a message digest for the given input.
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*
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* @param input The message to encrypt.
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* @return The digest (hash sum).
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*/
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public abstract byte[] digest(byte[] input);
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}
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