001    /**
002     *  Licensed to the Apache Software Foundation (ASF) under one or more
003     *  contributor license agreements.  See the NOTICE file distributed with
004     *  this work for additional information regarding copyright ownership.
005     *  The ASF licenses this file to You under the Apache License, Version 2.0
006     *  (the "License"); you may not use this file except in compliance with
007     *  the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    
018    package org.apache.geronimo.util.crypto;
019    
020    /**
021     * interface that a message digest conforms to.
022     */
023    public interface Digest
024    {
025        /**
026         * return the algorithm name
027         *
028         * @return the algorithm name
029         */
030        public String getAlgorithmName();
031    
032        /**
033         * return the size, in bytes, of the digest produced by this message digest.
034         *
035         * @return the size, in bytes, of the digest produced by this message digest.
036         */
037        public int getDigestSize();
038    
039        /**
040         * update the message digest with a single byte.
041         *
042         * @param in the input byte to be entered.
043         */
044        public void update(byte in);
045    
046        /**
047         * update the message digest with a block of bytes.
048         *
049         * @param in the byte array containing the data.
050         * @param inOff the offset into the byte array where the data starts.
051         * @param len the length of the data.
052         */
053        public void update(byte[] in, int inOff, int len);
054    
055        /**
056         * close the digest, producing the final digest value. The doFinal
057         * call leaves the digest reset.
058         *
059         * @param out the array the digest is to be copied into.
060         * @param outOff the offset into the out array the digest is to start at.
061         */
062        public int doFinal(byte[] out, int outOff);
063    
064        /**
065         * reset the digest back to it's initial state.
066         */
067        public void reset();
068    }