Java tutorial
package org.bouncycastle.crypto; /** * interface that a message digest conforms to. */ public interface Digest { /** * return the algorithm name * * @return the algorithm name */ public String getAlgorithmName(); /** * return the size, in bytes, of the digest produced by this message digest. * * @return the size, in bytes, of the digest produced by this message digest. */ public int getDigestSize(); /** * update the message digest with a single byte. * * @param in the input byte to be entered. */ public void update(byte in); /** * update the message digest with a block of bytes. * * @param in the byte array containing the data. * @param inOff the offset into the byte array where the data starts. * @param len the length of the data. */ public void update(byte[] in, int inOff, int len); /** * close the digest, producing the final digest value. The doFinal * call leaves the digest reset. * * @param out the array the digest is to be copied into. * @param outOff the offset into the out array the digest is to start at. */ public int doFinal(byte[] out, int outOff); /** * reset the digest back to it's initial state. */ public void reset(); }