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java.lang.Objectjava.security.MessageDigestSpi
public abstract class MessageDigestSpi
This is the Service Provider Interface (SPI) for MessageDigest class in java.security. It provides the back end functionality for the MessageDigest class so that it can compute message hashes. The default hashes are SHA-1 and MD5. A message hash takes data of arbitrary length and produces a unique number representing it. Cryptography service providers who want to implement their own message digest hashes need only to subclass this class. The implementation of a Cloneable interface is left to up to the programmer of a subclass.
Constructor Summary | |
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MessageDigestSpi()
Default constructor of the MessageDigestSpi class |
Method Summary | |
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Object |
clone()
Returns a clone of this class. |
protected abstract byte[] |
engineDigest()
Computes the final digest of the stored bytes and returns them. |
protected int |
engineDigest(byte[] buf,
int offset,
int len)
Computes the final digest of the stored bytes and returns them. |
protected int |
engineGetDigestLength()
Returns the length of the digest. |
protected abstract void |
engineReset()
Resets the digest engine. |
protected abstract void |
engineUpdate(byte input)
Updates the digest with the specified byte. |
protected abstract void |
engineUpdate(byte[] input,
int offset,
int len)
Updates the digest with the specified bytes starting with the offset and proceeding for the specified length. |
protected void |
engineUpdate(ByteBuffer input)
Updates this digest with the remaining bytes of a byte buffer. |
Methods inherited from class java.lang.Object |
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equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public MessageDigestSpi()
Method Detail |
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protected int engineGetDigestLength()
protected abstract void engineUpdate(byte input)
input
- the byte to update digest withprotected abstract void engineUpdate(byte[] input, int offset, int len)
input
- the byte array to update digest withoffset
- the offset of the byte to start withlen
- the number of the bytes to update withprotected void engineUpdate(ByteBuffer input)
input
- The input buffer.protected abstract byte[] engineDigest()
protected int engineDigest(byte[] buf, int offset, int len) throws DigestException
buf
- An array of bytes to store the digestoffset
- An offset to start storing the digest atlen
- The length of the buffer
DigestException
protected abstract void engineReset()
public Object clone() throws CloneNotSupportedException
clone
in class Object
CloneNotSupportedException
- If this Object does not
implement CloneableCloneable
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