* #### Mac
protected Mac([MacSpi](MacSpi.html "class in javax.crypto") macSpi,
[Provider](../../java/security/Provider.html "class in java.security") provider,
[String](../../java/lang/String.html "class in java.lang") algorithm)
Creates a MAC object.
Parameters:
`macSpi` \- the delegate
`provider` \- the provider
`algorithm` \- the algorithm
Method Detail
* #### getAlgorithm
public final [String](../../java/lang/String.html "class in java.lang") getAlgorithm()
Returns the algorithm name of this `Mac` object.
This is the same name that was specified in one of the`getInstance` calls that created this`Mac` object.
Returns:
the algorithm name of this `Mac` object.
* #### getInstance
public static final [Mac](Mac.html "class in javax.crypto") getInstance([String](../../java/lang/String.html "class in java.lang") algorithm)
throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")
Returns a `Mac` object that implements the specified MAC algorithm.
This method traverses the list of registered security Providers, starting with the most preferred Provider. A new Mac object encapsulating the MacSpi 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()](../../java/security/Security.html#getProviders%28%29) method.
Implementation Note:
The JDK Reference Implementation additionally uses the`jdk.security.provider.preferred` [Security](../../java/security/Security.html#getProperty%28java.lang.String%29) property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by[Security.getProviders()](../../java/security/Security.html#getProviders%28%29).
Parameters:
`algorithm` \- the standard name of the requested MAC algorithm. See the Mac section in the [ Java Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#mac-algorithms) for information about standard algorithm names.
Returns:
the new `Mac` object
Throws:
`[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if no `Provider` supports a`MacSpi` implementation for the specified algorithm
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`
See Also:
[Provider](../../java/security/Provider.html "class in java.security")
* #### getInstance
public static final [Mac](Mac.html "class in javax.crypto") getInstance([String](../../java/lang/String.html "class in java.lang") algorithm,
[String](../../java/lang/String.html "class in java.lang") provider)
throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security"),
[NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security")
Returns a `Mac` object that implements the specified MAC algorithm.
A new Mac object encapsulating the MacSpi 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()](../../java/security/Security.html#getProviders%28%29) method.
Parameters:
`algorithm` \- the standard name of the requested MAC algorithm. See the Mac section in the [ Java Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#mac-algorithms) for information about standard algorithm names.
`provider` \- the name of the provider.
Returns:
the new `Mac` object
Throws:
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the `provider` is `null` or empty
`[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if a `MacSpi` implementation for the specified algorithm is not available from the specified provider
`[NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security")` \- if the specified provider is not registered in the security provider list
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`
See Also:
[Provider](../../java/security/Provider.html "class in java.security")
* #### getInstance
public static final [Mac](Mac.html "class in javax.crypto") getInstance([String](../../java/lang/String.html "class in java.lang") algorithm,
[Provider](../../java/security/Provider.html "class in java.security") provider)
throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")
Returns a `Mac` object that implements the specified MAC algorithm.
A new Mac object encapsulating the MacSpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.
Parameters:
`algorithm` \- the standard name of the requested MAC algorithm. See the Mac section in the [ Java Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#mac-algorithms) for information about standard algorithm names.
`provider` \- the provider.
Returns:
the new `Mac` object
Throws:
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the `provider` is`null`
`[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if a `MacSpi` implementation for the specified algorithm is not available from the specified `Provider` object
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`
See Also:
[Provider](../../java/security/Provider.html "class in java.security")
* #### getProvider
public final [Provider](../../java/security/Provider.html "class in java.security") getProvider()
Returns the provider of this `Mac` object.
Returns:
the provider of this `Mac` object.
* #### getMacLength
public final int getMacLength()
Returns the length of the MAC in bytes.
Returns:
the MAC length in bytes.
* #### init
public final void init([Key](../../java/security/Key.html "interface in java.security") key)
throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")
Initializes this `Mac` object with the given key.
Parameters:
`key` \- the key.
Throws:
`[InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for initializing this MAC.
* #### init
public final void init([Key](../../java/security/Key.html "interface in java.security") key,
[AlgorithmParameterSpec](../../java/security/spec/AlgorithmParameterSpec.html "interface in java.security.spec") params)
throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security"),
[InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")
Initializes this `Mac` object with the given key and algorithm parameters.
Parameters:
`key` \- the key.
`params` \- the algorithm parameters.
Throws:
`[InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for initializing this MAC.
`[InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")` \- if the given algorithm parameters are inappropriate for this MAC.
* #### update
public final void update(byte input)
throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Processes the given byte.
Parameters:
`input` \- the input byte to be processed.
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### update
public final void update(byte[] input)
throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Processes the given array of bytes.
Parameters:
`input` \- the array of bytes to be processed.
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### update
public final void update(byte[] input,
int offset,
int len)
throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Processes the first `len` bytes in `input`, starting at `offset` inclusive.
Parameters:
`input` \- the input buffer.
`offset` \- the offset in `input` where the input starts.
`len` \- the number of bytes to process.
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### update
public final void update([ByteBuffer](../../java/nio/ByteBuffer.html "class in java.nio") input)
Processes `input.remaining()` bytes in the ByteBuffer`input`, starting at `input.position()`. Upon return, the buffer's position will be equal to its limit; its limit will not have changed.
Parameters:
`input` \- the ByteBuffer
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
Since:
1.5
* #### doFinal
public final byte[] doFinal()
throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Finishes the MAC operation.
A call to this method resets this `Mac` object to the state it was in when previously initialized via a call to`init(Key)` or`init(Key, AlgorithmParameterSpec)`. That is, the object is reset and available to generate another MAC from the same key, if desired, via new calls to `update` and`doFinal`. (In order to reuse this `Mac` object with a different key, it must be reinitialized via a call to `init(Key)` or`init(Key, AlgorithmParameterSpec)`.
Returns:
the MAC result.
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### doFinal
public final void doFinal(byte[] output,
int outOffset)
throws [ShortBufferException](ShortBufferException.html "class in javax.crypto"),
[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Finishes the MAC operation.
A call to this method resets this `Mac` object to the state it was in when previously initialized via a call to`init(Key)` or`init(Key, AlgorithmParameterSpec)`. That is, the object is reset and available to generate another MAC from the same key, if desired, via new calls to `update` and`doFinal`. (In order to reuse this `Mac` object with a different key, it must be reinitialized via a call to `init(Key)` or`init(Key, AlgorithmParameterSpec)`.
The MAC result is stored in `output`, starting at`outOffset` inclusive.
Parameters:
`output` \- the buffer where the MAC result is stored
`outOffset` \- the offset in `output` where the MAC is stored
Throws:
`[ShortBufferException](ShortBufferException.html "class in javax.crypto")` \- if the given output buffer is too small to hold the result
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### doFinal
public final byte[] doFinal(byte[] input)
throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")
Processes the given array of bytes and finishes the MAC operation.
A call to this method resets this `Mac` object to the state it was in when previously initialized via a call to`init(Key)` or`init(Key, AlgorithmParameterSpec)`. That is, the object is reset and available to generate another MAC from the same key, if desired, via new calls to `update` and`doFinal`. (In order to reuse this `Mac` object with a different key, it must be reinitialized via a call to `init(Key)` or`init(Key, AlgorithmParameterSpec)`.
Parameters:
`input` \- data in bytes
Returns:
the MAC result.
Throws:
`[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this `Mac` has not been initialized.
* #### reset
public final void reset()
Resets this `Mac` object.
A call to this method resets this `Mac` object to the state it was in when previously initialized via a call to`init(Key)` or`init(Key, AlgorithmParameterSpec)`. That is, the object is reset and available to generate another MAC from the same key, if desired, via new calls to `update` and`doFinal`. (In order to reuse this `Mac` object with a different key, it must be reinitialized via a call to `init(Key)` or`init(Key, AlgorithmParameterSpec)`.
* #### clone
public final [Object](../../java/lang/Object.html "class in java.lang") clone()
throws [CloneNotSupportedException](../../java/lang/CloneNotSupportedException.html "class in java.lang")
Returns a clone if the provider implementation is cloneable.
Overrides:
`[clone](../../java/lang/Object.html#clone%28%29)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Returns:
a clone if the provider implementation is cloneable.
Throws:
`[CloneNotSupportedException](../../java/lang/CloneNotSupportedException.html "class in java.lang")` \- if this is called on a delegate that does not support `Cloneable`.
See Also:
[Cloneable](../../java/lang/Cloneable.html "interface in java.lang")