oracle.security.crypto.core
Class MessageDigest

java.lang.Object
oracle.security.crypto.core.MessageDigest

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

HMAC, MD2, MD4, MD5, PasswordBasedMAC, SHA

public abstract class MessageDigest

extends java.lang.Object

implements java.lang.Cloneable

A generic class for computing message digests. Instantiate a subclass to implement a particular message digest algorithm (e.g., MD5).

To use, call one or more update() methods in sequence, then call computeCurrent(). The result of the digest computation can then be obtained using the getDigestBits() method.

The init() method may be called to reset the digest to its initial state. The digestValid field indicates whether the value of digestBits is valid, that is, no calls to update() or init() have been made since the last call to computeCurrent().

Nested Class Summary

class

MessageDigest.MDState Class representing the current state of a message digest object.

Field Summary

protected AlgorithmIdentifier	algID
byte[]	digestBits The result of the hash computation.
boolean	digestValid Indicates whether the value of digestBits is valid.

Constructor Summary

protected

MessageDigest() Creates a new message digest object.

Method Summary

abstract java.lang.String	algName() Returns the algorithm name of this message digest.
abstract int	blockSize()
abstract java.lang.Object	clone() Returns a clone of this message digest object.
abstract void	computeCurrent() Completes the hash computation, performing any necessary operations such as padding.
byte[]	computeDigest(byte[] source) Performs a complete digest operation on the given array of bytes.
byte[]	computeDigest(Streamable o)
abstract AlgorithmIdentifier	getAlgID()
byte[]	getDigestBits() Returns a copy of the current digest bytes.
abstract int	getDigestLength() Returns the length in bytes of the message digest.
static MessageDigest	getInstance(AlgorithmIdentifier algID)
protected abstract MessageDigest.MDState	getState()
abstract void	init() Resets this message digest object to its initial state.
boolean	isEqual(byte[] otherDigest) Compares this digest to the specified digest for equality.
static boolean	isEqual(byte[] digesta, byte[] digestb) Deprecated. Use Utils.areEqual(byte[], byte[]) instead.
void	setAlgID(AlgorithmIdentifier algID)
protected abstract void	setState(MessageDigest.MDState state)
java.lang.String	toString() Returns a string representation of this message digest object.
void	update(boolean aValue) Adds one byte to the data being digested, either 1 (if the given boolean value is true), or 0 (if the given boolean value is false).
abstract void	update(byte aValue) Adds the specifed byte to the data being digested.
void	update(byte[] input) Adds the specified array of bytes to the data being digested.
void	update(byte[] input, int off, int len) Adds the specified sequence of bytes to the data being digested.
void	update(java.io.InputStream in) Adds characters from the specified input stream to the data being digested, until end of stream is reached.
void	update(int aValue) Adds four bytes -- the big-endian representation of the specified int value -- to the data being digested.
void	update(int[] input) Adds the specified array of int values to the data being digested, using big-endian representation.
void	update(long aValue) Adds eight bytes -- the big-endian representation of the specified long value -- to the data being digested.
void	update(long[] input) Adds the specified array of long values to the data being digested, using big-endian representation.
void	update(short aValue) Adds two bytes -- the big-endian representation of the specified short value -- to the data being digested.
void	update(short[] input) Adds the specified array of short values to the data being digested, using big-endian representation.
void	update(java.lang.String input) Adds the characters of the specified string to the data being digested.
void	updateASCII(java.lang.String input) Adds the characters of the specified string to the data being digested.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

digestBits

public byte[] digestBits

The result of the hash computation.

digestValid

public boolean digestValid

Indicates whether the value of digestBits is valid.

algID

protected AlgorithmIdentifier algID

Constructor Detail

MessageDigest

protected MessageDigest()

Creates a new message digest object. The message digest is initialized automatically.

Method Detail

setAlgID

public void setAlgID(AlgorithmIdentifier algID)
              throws AlgorithmIdentifierException

Throws:

AlgorithmIdentifierException

getAlgID

public abstract AlgorithmIdentifier getAlgID()

blockSize

public abstract int blockSize()

getInstance

public static MessageDigest getInstance(AlgorithmIdentifier algID)
                                 throws AlgorithmIdentifierException

Throws:

AlgorithmIdentifierException

init

public abstract void init()

Resets this message digest object to its initial state.

update

public abstract void update(byte aValue)

Adds the specifed byte to the data being digested.

update

public void update(boolean aValue)

Adds one byte to the data being digested, either 1 (if the given boolean value is true), or 0 (if the given boolean value is false).

update

public void update(short aValue)

Adds two bytes -- the big-endian representation of the specified short value -- to the data being digested.

update

public void update(int aValue)

Adds four bytes -- the big-endian representation of the specified int value -- to the data being digested.

update

public void update(long aValue)

Adds eight bytes -- the big-endian representation of the specified long value -- to the data being digested.

update

public void update(byte[] input,
                   int off,
                   int len)

Adds the specified sequence of bytes to the data being digested.

Parameters:

input - the input array

off - start position in the input array

len - the number of input array elements to add to the data being digested

update

public void update(byte[] input)

Adds the specified array of bytes to the data being digested.

update

public void update(short[] input)

Adds the specified array of short values to the data being digested, using big-endian representation.

update

public void update(int[] input)

Adds the specified array of int values to the data being digested, using big-endian representation.

update

public void update(long[] input)

Adds the specified array of long values to the data being digested, using big-endian representation.

update

public void update(java.lang.String input)

Adds the characters of the specified string to the data being digested.

Each character is treated as a 16-bit value, and is appended in big-endian order.

updateASCII

public void updateASCII(java.lang.String input)

Adds the characters of the specified string to the data being digested.

Each character is treated as a ISO-Latin1 (8-bit) character.

update

public void update(java.io.InputStream in)
            throws java.io.IOException

Adds characters from the specified input stream to the data being digested, until end of stream is reached.

Throws:

java.io.IOException

computeCurrent

public abstract void computeCurrent()

Completes the hash computation, performing any necessary operations such as padding. The result of the hash can be obtained using getDigestBits().

getDigestBits

public byte[] getDigestBits()

Returns a copy of the current digest bytes.

computeDigest

public byte[] computeDigest(byte[] source)

Performs a complete digest operation on the given array of bytes.

That is, first init() is called, then the byte array is given to update, then computeCurrent() is called.

computeDigest

public byte[] computeDigest(Streamable o)
                     throws java.io.IOException

Throws:

java.io.IOException

isEqual

public static boolean isEqual(byte[] digesta,
                              byte[] digestb)

Deprecated. Use Utils.areEqual(byte[], byte[]) instead.

Compares two digests for equality. Simple byte comparison.

Parameters:

digesta - the first digest bytes

digestb - the second digest bytes

isEqual

public boolean isEqual(byte[] otherDigest)

Compares this digest to the specified digest for equality. Simple byte comparison.

algName

public abstract java.lang.String algName()

Returns the algorithm name of this message digest.

getDigestLength

public abstract int getDigestLength()

Returns the length in bytes of the message digest.

toString

public java.lang.String toString()

Returns a string representation of this message digest object.

clone

public abstract java.lang.Object clone()

Returns a clone of this message digest object.

getState

protected abstract MessageDigest.MDState getState()

setState

protected abstract void setState(MessageDigest.MDState state)