This MessageDigest class provides applications the functionality of a message digest algorithm, such as SHA-1 or SHA-256. Message digests are secure one-way hash functions that take arbitrary-sized data and output a fixed-length hash value.

A MessageDigest object starts out initialized. The data is processed through it using the update methods. At any point reset can be called to reset the digest. Once all the data to be updated has been updated, one of the digest methods should be called to complete the hash computation.

The digest method can be called once for a given number of updates. After digest has been called, the MessageDigest object is reset to its initialized state.

Implementations are free to implement the Cloneable interface. Client applications can test cloneability by attempting cloning and catching the CloneNotSupportedException:

MessageDigest md = MessageDigest.getInstance("SHA-256");

try {
    md.update(toChapter1);
    MessageDigest tc1 = md.clone();
    byte[] toChapter1Digest = tc1.digest();
    md.update(toChapter2);
    ...etc.
} catch (CloneNotSupportedException cnse) {
    throw new DigestException("couldn't make digest of partial content");
}

Note that if a given implementation is not cloneable, it is still possible to compute intermediate digests by instantiating several instances, if the number of digests is known in advance.

Note that this class is abstract and extends from MessageDigestSpi for historical reasons. Application developers should only take notice of the methods defined in this MessageDigest class; all the methods in the superclass are intended for cryptographic service providers who wish to supply their own implementations of message digest algorithms.

Every implementation of the Java platform is required to support the following standard MessageDigest algorithms:

SHA-1
SHA-256

These algorithms are described in the MessageDigest section of the Java Security Standard Algorithm Names Specification. Consult the release documentation for your implementation to see if any other algorithms are supported.

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	MessageDigest.Delegate

Field Summary

Modifier and Type	Field and Description
private final String	algorithm
private static final int	IN_PROGRESS
private static final int	INITIAL
private static final Debug	pdebug
private Provider	provider
private static final boolean	skipDebug
private int	state

Constructor Summary

Access	Constructor and Description
protected	MessageDigest(String the standard name of the digest algorithm. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. algorithm) Creates a message digest with the specified algorithm name.
private	MessageDigest(String algorithm, Provider p)

Method Summary

Modifier and Type	Method and Description
public Object	Returns: a clone if the implementation is cloneable. clone() Overrides java.security.MessageDigestSpi.clone. Returns a clone if the implementation is cloneable.
public byte[]	Returns: the array of bytes for the resulting hash value. digest() Completes the hash computation by performing final operations such as padding.
public int	Returns: the number of bytes placed into `buf` digest(byte[] output buffer for the computed digest buf, int offset into the output buffer to begin storing the digest offset, int number of bytes within buf allotted for the digest len) Completes the hash computation by performing final operations such as padding.
public byte[]	Returns: the array of bytes for the resulting hash value. digest(byte[] the input to be updated before the digest is completed. input) Performs a final update on the digest using the specified array of bytes, then completes the digest computation.
public final String	Returns: the name of the algorithm getAlgorithm() Returns a string that identifies the algorithm, independent of implementation details.
public final int	Returns: the digest length in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable. getDigestLength() Returns the length of the digest in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable.
public static MessageDigest	Returns: a `MessageDigest` object that implements the specified algorithm getInstance(String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. algorithm) Returns a `MessageDigest` object that implements the specified digest algorithm.
public static MessageDigest	Returns: a `MessageDigest` object that implements the specified algorithm getInstance(String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. algorithm, String the name of the provider. provider) Returns a `MessageDigest` object that implements the specified digest algorithm.
public static MessageDigest	Returns: a `MessageDigest` object that implements the specified algorithm getInstance(String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. algorithm, Provider the provider. provider) Returns a `MessageDigest` object that implements the specified digest algorithm.
public final Provider	Returns: the provider of this message digest object getProvider() Returns the provider of this message digest object.
private String	getProviderName()
public static boolean	Returns: `true` if the digests are equal, `false` otherwise. isEqual(byte[] one of the digests to compare. digesta, byte[] the other digest to compare. digestb) Compares two digests for equality.
public void	reset() Resets the digest for further use.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of this message digest object.
public void	update(byte the byte with which to update the digest. input) Updates the digest using the specified byte.
public void	update(byte[] the array of bytes. input, int the offset to start from in the array of bytes. offset, int the number of bytes to use, starting at `offset`. len) Updates the digest using the specified array of bytes, starting at the specified offset.
public void	update(byte[] the array of bytes. input) Updates the digest using the specified array of bytes.
public final void	update(ByteBuffer the ByteBuffer input) Update the digest using the specified ByteBuffer.

Inherited from java.security.MessageDigestSpi:: engineDigest engineDigest engineGetDigestLength engineReset engineUpdate engineUpdate engineUpdate

Field Detail

algorithm	back to summary
private final String algorithm

IN_PROGRESS	back to summary
private static final int IN_PROGRESS

INITIAL	back to summary
private static final int INITIAL

pdebug	back to summary
private static final Debug pdebug

provider	back to summary
private Provider provider

skipDebug	back to summary
private static final boolean skipDebug

state	back to summary
private int state

Constructor Detail

MessageDigest	back to summary
protected MessageDigest(String algorithm) Creates a message digest with the specified algorithm name. Parameters algorithm:String the standard name of the digest algorithm. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.

MessageDigest

back to summary

protected MessageDigest(String algorithm)

Creates a message digest with the specified algorithm name.

Parameters

algorithm:String: the standard name of the digest algorithm. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.

MessageDigest	back to summary
private MessageDigest(String algorithm, Provider p)

Method Detail

clone back to summary

clone	back to summary
public Object clone() throws CloneNotSupportedException Overrides java.security.MessageDigestSpi.clone. Returns a clone if the implementation is cloneable. Returns:Object a clone if the implementation is cloneable. Exceptions CloneNotSupportedException: if this is called on an implementation that does not support `Cloneable`.

public Object clone() throws CloneNotSupportedException

Overrides java.security.MessageDigestSpi.clone.

Returns a clone if the implementation is cloneable.

Returns:Object

a clone if the implementation is cloneable.

Exceptions

CloneNotSupportedException:: if this is called on an implementation that does not support Cloneable.

digest	back to summary
public byte[] digest() Completes the hash computation by performing final operations such as padding. The digest is reset after this call is made. Returns:byte[] the array of bytes for the resulting hash value.

digest

back to summary

public byte[] digest()

Completes the hash computation by performing final operations such as padding. The digest is reset after this call is made.

Returns:byte[]: the array of bytes for the resulting hash value.

digest back to summary

digest	back to summary
public int digest(byte[] buf, int offset, int len) throws DigestException Completes the hash computation by performing final operations such as padding. The digest is reset after this call is made. Parameters buf:byte[] output buffer for the computed digest offset:int offset into the output buffer to begin storing the digest len:int number of bytes within buf allotted for the digest Returns:int the number of bytes placed into `buf` Exceptions DigestException: if an error occurs.

public int digest(byte[] buf, int offset, int len) throws DigestException

Completes the hash computation by performing final operations such as padding. The digest is reset after this call is made.

Parameters

buf:byte[]: output buffer for the computed digest
offset:int: offset into the output buffer to begin storing the digest
len:int: number of bytes within buf allotted for the digest

Returns:int

the number of bytes placed into buf

Exceptions

DigestException:: if an error occurs.

digest back to summary

digest	back to summary
public byte[] digest(byte[] input) Performs a final update on the digest using the specified array of bytes, then completes the digest computation. That is, this method first calls `update(input)`, passing the input array to the `update` method, then calls `digest()`. Parameters input:byte[] the input to be updated before the digest is completed. Returns:byte[] the array of bytes for the resulting hash value.

public byte[] digest(byte[] input)

Performs a final update on the digest using the specified array of bytes, then completes the digest computation. That is, this method first calls update(input), passing the input array to the update method, then calls digest().

Parameters

input:byte[]: the input to be updated before the digest is completed.

Returns:byte[]

the array of bytes for the resulting hash value.

getAlgorithm	back to summary
public final String getAlgorithm() Returns a string that identifies the algorithm, independent of implementation details. The name should be a standard Java Security name (such as "SHA-256"). See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. Returns:String the name of the algorithm

getAlgorithm

back to summary

public final String getAlgorithm()

Returns a string that identifies the algorithm, independent of implementation details. The name should be a standard Java Security name (such as "SHA-256"). See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.

Returns:String: the name of the algorithm

getDigestLength	back to summary
public final int getDigestLength() Returns the length of the digest in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable. Returns:int the digest length in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable. Since 1.2

getDigestLength

back to summary

public final int getDigestLength()

Returns the length of the digest in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable.

Returns:int: the digest length in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable.
Since: 1.2

getInstance back to summary

getInstance	back to summary
public static MessageDigest getInstance(String algorithm) throws NoSuchAlgorithmException Returns a `MessageDigest` object that implements the specified digest algorithm. This method traverses the list of registered security Providers, starting with the most preferred Provider. A new `MessageDigest` object encapsulating the `MessageDigestSpi` implementation from the first provider that supports the specified algorithm is returned. Note that the list of registered providers may be retrieved via the `Security.getProviders()` method. Implementation Note The JDK Reference Implementation additionally uses the `jdk.security.provider.preferred` `Security` property to determine the preferred provider order for the specified algorithm. This may be different from the order of providers returned by `Security.getProviders()`. Parameters algorithm:String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. Returns:MessageDigest a `MessageDigest` object that implements the specified algorithm Exceptions NoSuchAlgorithmException: if no `Provider` supports a `MessageDigestSpi` implementation for the specified algorithm NullPointerException: if `algorithm` is `null` See Also `Provider`

public static MessageDigest getInstance(String algorithm) throws NoSuchAlgorithmException

Returns a MessageDigest object that implements the specified digest algorithm.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new MessageDigest object encapsulating the MessageDigestSpi implementation from the first provider that supports the specified algorithm is returned.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

Implementation Note

The JDK Reference Implementation additionally uses the jdk.security.provider.preferred Security property to determine the preferred provider order for the specified algorithm. This may be different from the order of providers returned by Security.getProviders().

Parameters

algorithm:String: the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.

Returns:MessageDigest

a MessageDigest object that implements the specified algorithm

Exceptions

NoSuchAlgorithmException:: if no Provider supports a MessageDigestSpi implementation for the specified algorithm
NullPointerException:: if algorithm is null

See Also

Provider

getInstance back to summary

getInstance	back to summary
public static MessageDigest getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException Returns a `MessageDigest` object that implements the specified digest algorithm. A new `MessageDigest` object encapsulating the `MessageDigestSpi` implementation from the specified provider is returned. The specified provider must be registered in the security provider list. Note that the list of registered providers may be retrieved via the `Security.getProviders()` method. Parameters algorithm:String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. provider:String the name of the provider. Returns:MessageDigest a `MessageDigest` object that implements the specified algorithm Exceptions NoSuchAlgorithmException: if a `MessageDigestSpi` implementation for the specified algorithm is not available from the specified provider NoSuchProviderException: if the specified provider is not registered in the security provider list IllegalArgumentException: if the provider name is `null` or empty NullPointerException: if `algorithm` is `null` See Also `Provider`

public static MessageDigest getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException

Returns a MessageDigest object that implements the specified digest algorithm.

A new MessageDigest object encapsulating the MessageDigestSpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

Parameters

algorithm:String: the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
provider:String: the name of the provider.

Returns:MessageDigest

a MessageDigest object that implements the specified algorithm

Exceptions

NoSuchAlgorithmException:: if a MessageDigestSpi implementation for the specified algorithm is not available from the specified provider
NoSuchProviderException:: if the specified provider is not registered in the security provider list
IllegalArgumentException:: if the provider name is null or empty
NullPointerException:: if algorithm is null

See Also

Provider

getInstance back to summary

getInstance	back to summary
public static MessageDigest getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException Returns a `MessageDigest` object that implements the specified digest algorithm. A new `MessageDigest` object encapsulating the `MessageDigestSpi` implementation from the specified provider is returned. Note that the specified provider does not have to be registered in the provider list. Parameters algorithm:String the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names. provider:Provider the provider. Returns:MessageDigest a `MessageDigest` object that implements the specified algorithm Exceptions NoSuchAlgorithmException: if a `MessageDigestSpi` implementation for the specified algorithm is not available from the specified `Provider` object IllegalArgumentException: if the specified provider is `null` NullPointerException: if `algorithm` is `null` Since 1.4 See Also `Provider`

public static MessageDigest getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException

Returns a MessageDigest object that implements the specified digest algorithm.

A new MessageDigest object encapsulating the MessageDigestSpi implementation from the specified provider is returned. Note that the specified provider does not have to be registered in the provider list.

Parameters

algorithm:String: the name of the algorithm requested. See the MessageDigest section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
provider:Provider: the provider.

Returns:MessageDigest

a MessageDigest object that implements the specified algorithm

Exceptions

NoSuchAlgorithmException:: if a MessageDigestSpi implementation for the specified algorithm is not available from the specified Provider object
IllegalArgumentException:: if the specified provider is null
NullPointerException:: if algorithm is null

Since

1.4

See Also

Provider

getProvider	back to summary
public final Provider getProvider() Returns the provider of this message digest object. Returns:Provider the provider of this message digest object

getProvider

back to summary

public final Provider getProvider()

Returns the provider of this message digest object.

Returns:Provider: the provider of this message digest object

getProviderName	back to summary
private String getProviderName()

isEqual back to summary

isEqual	back to summary
public static boolean isEqual(byte[] digesta, byte[] digestb) Compares two digests for equality. Two digests are equal if they have the same length and all bytes at corresponding positions are equal. Implementation Note All bytes in `digesta` are examined to determine equality, unless `digestb` is `null` or has a length of zero bytes. If `digestb` is not `null` and does not have a length of zero bytes, then the calculation time depends only on the length of `digesta`. It does not depend on the length of `digestb` or the contents of `digesta` and `digestb`. Parameters digesta:byte[] one of the digests to compare. digestb:byte[] the other digest to compare. Returns:boolean `true` if the digests are equal, `false` otherwise.

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

Compares two digests for equality. Two digests are equal if they have the same length and all bytes at corresponding positions are equal.

Implementation Note

All bytes in digesta are examined to determine equality, unless digestb is null or has a length of zero bytes. If digestb is not null and does not have a length of zero bytes, then the calculation time depends only on the length of digesta. It does not depend on the length of digestb or the contents of digesta and digestb.

Parameters

digesta:byte[]: one of the digests to compare.
digestb:byte[]: the other digest to compare.

Returns:boolean

true if the digests are equal, false otherwise.

reset	back to summary
public void reset() Resets the digest for further use.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Returns a string representation of this message digest object. Returns:String Doc from java.lang.Object.toString. a string representation of the object

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Returns a string representation of this message digest object.

Returns:String

Doc from java.lang.Object.toString.

a string representation of the object

update	back to summary
public void update(byte input) Updates the digest using the specified byte. Parameters input:byte the byte with which to update the digest.

update

back to summary

public void update(byte input)

Updates the digest using the specified byte.

Parameters

input:byte: the byte with which to update the digest.

update back to summary

update	back to summary
public void update(byte[] input, int offset, int len) Updates the digest using the specified array of bytes, starting at the specified offset. Parameters input:byte[] the array of bytes. offset:int the offset to start from in the array of bytes. len:int the number of bytes to use, starting at `offset`.

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

Updates the digest using the specified array of bytes, starting at the specified offset.

Parameters

input:byte[]: the array of bytes.
offset:int: the offset to start from in the array of bytes.
len:int: the number of bytes to use, starting at offset.

update	back to summary
public void update(byte[] input) Updates the digest using the specified array of bytes. Parameters input:byte[] the array of bytes.

update

back to summary

public void update(byte[] input)

Updates the digest using the specified array of bytes.

Parameters

input:byte[]: the array of bytes.

update back to summary

update	back to summary
public final void update(ByteBuffer input) Update the digest using the specified ByteBuffer. The digest is updated using the `input.remaining()` bytes starting at `input.position()`. Upon return, the buffer's position will be equal to its limit; its limit will not have changed. Parameters input:ByteBuffer the ByteBuffer Since 1.5

public final void update(ByteBuffer input)

Update the digest using the specified ByteBuffer. The digest is updated using the input.remaining() bytes starting at input.position(). Upon return, the buffer's position will be equal to its limit; its limit will not have changed.

Parameters

input:ByteBuffer: the ByteBuffer

Since

1.5

java.security back to summary

private Class MessageDigest.Delegate

Class Inheritance

extends MessageDigest
implements MessageDigestSpi2

All Implemented Interfaces

sun.security.util.MessageDigestSpi2

Known Direct Subclasses

java.security.MessageDigest.Delegate.CloneableDelegate

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	MessageDigest.Delegate.CloneableDelegate

Field Summary

Modifier and Type	Field and Description
private final MessageDigestSpi	digestSpi

Constructor Summary

Access	Constructor and Description
private	Delegate(MessageDigestSpi digestSpi, String algorithm, Provider p)

Method Summary

Modifier and Type	Method and Description
public Object	Returns: a clone if the delegate is cloneable. clone() Overrides java.security.MessageDigest.clone. Returns a clone if the delegate is cloneable.
protected byte[]	engineDigest() Implements abstract java.security.MessageDigestSpi.engineDigest. Completes the hash computation by performing final operations such as padding.
protected int	engineDigest(byte[] the output buffer in which to store the digest buf, int offset to start from in the output buffer offset, int number of bytes within `buf` allotted for the digest. Both this default implementation and the SUN provider do not return partial digests. The presence of this parameter is solely for consistency in our API's. If the value of this parameter is less than the actual digest length, the method will throw a `DigestException`. This parameter is ignored if its value is greater than or equal to the actual digest length. len) Overrides java.security.MessageDigestSpi.engineDigest. Completes the hash computation by performing final operations such as padding.
protected int	engineGetDigestLength() Overrides java.security.MessageDigestSpi.engineGetDigestLength. Returns the digest length in bytes.
protected void	engineReset() Implements abstract java.security.MessageDigestSpi.engineReset. Resets the digest for further use.
protected void	engineUpdate(byte the byte to use for the update. input) Implements abstract java.security.MessageDigestSpi.engineUpdate. Updates the digest using the specified byte.
protected void	engineUpdate(byte[] the array of bytes to use for the update. input, int the offset to start from in the array of bytes. offset, int the number of bytes to use, starting at `offset`. len) Implements abstract java.security.MessageDigestSpi.engineUpdate. Updates the digest using the specified array of bytes, starting at the specified offset.
protected void	engineUpdate(ByteBuffer the ByteBuffer input) Overrides java.security.MessageDigestSpi.engineUpdate. Update the digest using the specified ByteBuffer.
public void	engineUpdate(SecretKey the key whose value is to be digested. key) Implements sun.security.util.MessageDigestSpi2.engineUpdate. Updates the digest using the specified key.
pack-priv static MessageDigest.Delegate	of(MessageDigestSpi digestSpi, String algo, Provider p)

Inherited from java.security.MessageDigest:: digest digest digest getAlgorithm getDigestLength getInstance getInstance getInstance getProvider isEqual reset toString update update update update

Field Detail

digestSpi	back to summary
private final MessageDigestSpi digestSpi

Constructor Detail

Delegate	back to summary
private Delegate(MessageDigestSpi digestSpi, String algorithm, Provider p)

Method Detail

clone back to summary

clone	back to summary
public Object clone() throws CloneNotSupportedException Overrides java.security.MessageDigest.clone. Returns a clone if the delegate is cloneable. Returns:Object a clone if the delegate is cloneable. Annotations @Override Exceptions CloneNotSupportedException: if this is called on a delegate that does not support `Cloneable`.

public Object clone() throws CloneNotSupportedException

Overrides java.security.MessageDigest.clone.

Returns a clone if the delegate is cloneable.

Returns:Object

a clone if the delegate is cloneable.

Annotations

@Override

Exceptions

CloneNotSupportedException:: if this is called on a delegate that does not support Cloneable.

engineDigest back to summary

engineDigest	back to summary
protected byte[] engineDigest() Implements abstract java.security.MessageDigestSpi.engineDigest. Doc from java.security.MessageDigestSpi.engineDigest. Completes the hash computation by performing final operations such as padding. Once `engineDigest` has been called, the engine should be reset (see `engineReset`). Resetting is the responsibility of the engine implementor. Returns:byte[] the array of bytes for the resulting hash value. Annotations @Override

protected byte[] engineDigest()

Implements abstract java.security.MessageDigestSpi.engineDigest.

Doc from java.security.MessageDigestSpi.engineDigest.

Returns:byte[]

the array of bytes for the resulting hash value.

Annotations

@Override

engineDigest back to summary

engineDigest	back to summary
protected int engineDigest(byte[] buf, int offset, int len) throws DigestException Overrides java.security.MessageDigestSpi.engineDigest. Doc from java.security.MessageDigestSpi.engineDigest. Completes the hash computation by performing final operations such as padding. Once `engineDigest` has been called, the engine should be reset (see `engineReset`). Resetting is the responsibility of the engine implementor. This method should be abstract, but we leave it concrete for binary compatibility. Knowledgeable providers should override this method. Parameters buf:byte[] the output buffer in which to store the digest offset:int offset to start from in the output buffer len:int number of bytes within `buf` allotted for the digest. Both this default implementation and the SUN provider do not return partial digests. The presence of this parameter is solely for consistency in our API's. If the value of this parameter is less than the actual digest length, the method will throw a `DigestException`. This parameter is ignored if its value is greater than or equal to the actual digest length. Returns:int the length of the digest stored in the output buffer. Annotations @Override Exceptions DigestException: if an error occurs.

protected int engineDigest(byte[] buf, int offset, int len) throws DigestException

Overrides java.security.MessageDigestSpi.engineDigest.

Doc from java.security.MessageDigestSpi.engineDigest.

Completes the hash computation by performing final operations such as padding. Once engineDigest has been called, the engine should be reset (see engineReset). Resetting is the responsibility of the engine implementor. This method should be abstract, but we leave it concrete for binary compatibility. Knowledgeable providers should override this method.

Parameters

buf:byte[]: the output buffer in which to store the digest
offset:int: offset to start from in the output buffer
len:int: number of bytes within buf allotted for the digest. Both this default implementation and the SUN provider do not return partial digests. The presence of this parameter is solely for consistency in our API's. If the value of this parameter is less than the actual digest length, the method will throw a DigestException. This parameter is ignored if its value is greater than or equal to the actual digest length.

Returns:int

the length of the digest stored in the output buffer.

Annotations

@Override

Exceptions

DigestException:: if an error occurs.

engineGetDigestLength	back to summary
protected int engineGetDigestLength() Overrides java.security.MessageDigestSpi.engineGetDigestLength. Doc from java.security.MessageDigestSpi.engineGetDigestLength. Returns the digest length in bytes. This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) The default behavior is to return 0. This method may be overridden by a provider to return the digest length. Returns:int the digest length in bytes. Annotations @Override

engineGetDigestLength

back to summary

protected int engineGetDigestLength()

Overrides java.security.MessageDigestSpi.engineGetDigestLength.

Doc from java.security.MessageDigestSpi.engineGetDigestLength.

Returns the digest length in bytes.

This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.)

The default behavior is to return 0.

This method may be overridden by a provider to return the digest length.

Returns:int

the digest length in bytes.

Annotations

@Override

engineReset	back to summary
protected void engineReset() Implements abstract java.security.MessageDigestSpi.engineReset. Doc from java.security.MessageDigestSpi.engineReset. Resets the digest for further use. Annotations @Override

engineReset

back to summary

protected void engineReset()

Implements abstract java.security.MessageDigestSpi.engineReset.

Doc from java.security.MessageDigestSpi.engineReset.

Resets the digest for further use.

Annotations

@Override

engineUpdate	back to summary
protected void engineUpdate(byte input) Implements abstract java.security.MessageDigestSpi.engineUpdate. Doc from java.security.MessageDigestSpi.engineUpdate. Updates the digest using the specified byte. Parameters input:byte the byte to use for the update. Annotations @Override

engineUpdate

back to summary

protected void engineUpdate(byte input)

Implements abstract java.security.MessageDigestSpi.engineUpdate.

Doc from java.security.MessageDigestSpi.engineUpdate.

Updates the digest using the specified byte.

Parameters

input:byte: the byte to use for the update.

Annotations

@Override

engineUpdate back to summary

engineUpdate	back to summary
protected void engineUpdate(byte[] input, int offset, int len) Implements abstract java.security.MessageDigestSpi.engineUpdate. Doc from java.security.MessageDigestSpi.engineUpdate. Updates the digest using the specified array of bytes, starting at the specified offset. Parameters input:byte[] the array of bytes to use for the update. offset:int the offset to start from in the array of bytes. len:int the number of bytes to use, starting at `offset`. Annotations @Override

protected void engineUpdate(byte[] input, int offset, int len)

Implements abstract java.security.MessageDigestSpi.engineUpdate.

Doc from java.security.MessageDigestSpi.engineUpdate.

Updates the digest using the specified array of bytes, starting at the specified offset.

Parameters

input:byte[]: the array of bytes to use for the update.
offset:int: the offset to start from in the array of bytes.
len:int: the number of bytes to use, starting at offset.

Annotations

@Override

engineUpdate back to summary

engineUpdate	back to summary
protected void engineUpdate(ByteBuffer input) Overrides java.security.MessageDigestSpi.engineUpdate. Doc from java.security.MessageDigestSpi.engineUpdate. Update the digest using the specified ByteBuffer. The digest is updated using the `input.remaining()` bytes starting at `input.position()`. Upon return, the buffer's position will be equal to its limit; its limit will not have changed. Parameters input:ByteBuffer the ByteBuffer Annotations @Override

protected void engineUpdate(ByteBuffer input)

Overrides java.security.MessageDigestSpi.engineUpdate.

Doc from java.security.MessageDigestSpi.engineUpdate.

Parameters

input:ByteBuffer: the ByteBuffer

Annotations

@Override

engineUpdate	back to summary
public void engineUpdate(SecretKey key) throws InvalidKeyException Implements sun.security.util.MessageDigestSpi2.engineUpdate. Doc from sun.security.util.MessageDigestSpi2.engineUpdate. Updates the digest using the specified key. This is used for SSL 3.0 only, we may deprecate and remove the support of this in the future Parameters key:SecretKey the key whose value is to be digested. Annotations @Override

engineUpdate

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public void engineUpdate(SecretKey key) throws InvalidKeyException

Implements sun.security.util.MessageDigestSpi2.engineUpdate.

Doc from sun.security.util.MessageDigestSpi2.engineUpdate.

Updates the digest using the specified key. This is used for SSL 3.0 only, we may deprecate and remove the support of this in the future

Parameters

key:SecretKey: the key whose value is to be digested.

Annotations

@Override

of	back to summary
pack-priv static MessageDigest.Delegate of(MessageDigestSpi digestSpi, String algo, Provider p)

java.security back to summary

private final Class MessageDigest.Delegate.CloneableDelegate

Class Inheritance

extends Delegate
implements Cloneable

java.lang.Object
java.security.MessageDigestSpi
java.security.MessageDigest
java.security.MessageDigest.Delegate
java.security.MessageDigest.Delegate.CloneableDelegate

All Implemented Interfaces

java.lang.Cloneable

Constructor Summary

Access	Constructor and Description
private	CloneableDelegate(MessageDigestSpi digestSpi, String algorithm, Provider p)

Method Summary

Inherited from java.security.MessageDigest.Delegate:: clone engineDigest engineDigest engineGetDigestLength engineReset engineUpdate engineUpdate engineUpdate engineUpdate of

Constructor Detail

CloneableDelegate	back to summary
private CloneableDelegate(MessageDigestSpi digestSpi, String algorithm, Provider p)

public abstract Class MessageDigest

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class MessageDigest.Delegate

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private final Class MessageDigest.Delegate.CloneableDelegate

Constructor Summary

Method Summary

Constructor Detail