Added in API level 1

Mac

open class Mac : Cloneable

kotlin.Any
↳	javax.crypto.Mac

This class provides the functionality of a "Message Authentication Code" (MAC) algorithm.

A MAC provides a way to check the integrity of information transmitted over or stored in an unreliable medium, based on a secret key. Typically, message authentication codes are used between two parties that share a secret key in order to validate information transmitted between these parties.

A MAC mechanism that is based on cryptographic hash functions is referred to as HMAC. HMAC can be used with any cryptographic hash function, e.g., MD5 or SHA-1, in combination with a secret shared key. HMAC is specified in RFC 2104.

Android provides the following Mac algorithms:

Algorithm	Supported API Levels
AESCMAC	31+
DESMAC	1-8
DESMAC/CFB8	1-8
DESedeMAC	1-8
DESedeMAC/CFB8	1-8
DESedeMAC64	1-8
DESwithISO9797	1-8
HmacMD5	1+
HmacSHA1	1+
HmacSHA224	1-8,22+
HmacSHA256	1+
HmacSHA384	1+
HmacSHA512	1+
ISO9797ALG3MAC	1-8
PBEwithHmacSHA	1+
PBEwithHmacSHA1	1+
PBEwithHmacSHA224	26-31
PBEwithHmacSHA256	26-31
PBEwithHmacSHA384	26-31
PBEwithHmacSHA512	26-31

These algorithms are described in the Mac section of the Java Cryptography Architecture Standard Algorithm Name Documentation.

Summary

Protected constructors
Mac(macSpi: MacSpi!, provider: Provider!, algorithm: String!) Creates a MAC object.

Public methods
Any	clone() Returns a clone if the provider implementation is cloneable.
ByteArray!	doFinal() Finishes the MAC operation.
Unit	doFinal(output: ByteArray!, outOffset: Int) Finishes the MAC operation.
ByteArray!	doFinal(input: ByteArray!) Processes the given array of bytes and finishes the MAC operation.
String!	getAlgorithm() Returns the algorithm name of this Mac object.
static Mac!	getInstance(algorithm: String!) Returns a Mac object that implements the specified MAC algorithm.
static Mac!	getInstance(algorithm: String!, provider: String!) Returns a Mac object that implements the specified MAC algorithm.
static Mac!	getInstance(algorithm: String!, provider: Provider!) Returns a Mac object that implements the specified MAC algorithm.
Int	getMacLength() Returns the length of the MAC in bytes.
Provider!	getProvider() Returns the provider of this Mac object.
Unit	init(key: Key!) Initializes this Mac object with the given key.
Unit	init(key: Key!, params: AlgorithmParameterSpec!) Initializes this Mac object with the given key and algorithm parameters.
Unit	reset() Resets this Mac object.
Unit	update(input: Byte) Processes the given byte.
Unit	update(input: ByteArray!) Processes the given array of bytes.
Unit	update(input: ByteArray!, offset: Int, len: Int) Processes the first len bytes in input, starting at offset inclusive.
Unit	update(input: ByteBuffer!) Processes input.remaining() bytes in the ByteBuffer input, starting at input.position().

Protected constructors

Mac

Added in API level 1

protected Mac(
    macSpi: MacSpi!, 
    provider: Provider!, 
    algorithm: String!)

Creates a MAC object.

Parameters
macSpi	MacSpi!: the delegate
provider	Provider!: the provider
algorithm	String!: the algorithm

Public methods

clone

Added in API level 1

fun clone(): Any

Returns a clone if the provider implementation is cloneable.

Return
Any	a clone if the provider implementation is cloneable.

Exceptions
java.lang.CloneNotSupportedException	if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.
java.lang.CloneNotSupportedException	if this is called on a delegate that does not support Cloneable.

doFinal

Added in API level 1

fun doFinal(): ByteArray!

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).

Return
ByteArray!	the MAC result.

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.

doFinal

Added in API level 1

fun doFinal(
    output: ByteArray!, 
    outOffset: Int
): Unit

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	ByteArray!: the buffer where the MAC result is stored
outOffset	Int: the offset in output where the MAC is stored

Exceptions
javax.crypto.ShortBufferException	if the given output buffer is too small to hold the result
java.lang.IllegalStateException	if this Mac has not been initialized.

doFinal

Added in API level 1

fun doFinal(input: ByteArray!): ByteArray!

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	ByteArray!: data in bytes

Return
ByteArray!	the MAC result.

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.

getAlgorithm

Added in API level 1

fun getAlgorithm(): String!

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.

Return
String!	the algorithm name of this Mac object.

getInstance

Added in API level 1

static fun getInstance(algorithm: String!): Mac!

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() method.

Parameters
algorithm	String!: the standard name of the requested MAC algorithm. See the Mac section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.

Return
Mac!	the new Mac object.

Exceptions
java.security.NoSuchAlgorithmException	if no Provider supports a MacSpi implementation for the specified algorithm.

See Also

• java.security.Provider

getInstance

Added in API level 1

static fun getInstance(
    algorithm: String!, 
    provider: String!
): Mac!

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() method.

Parameters
algorithm	String!: the standard name of the requested MAC algorithm. See the Mac section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
provider	String!: the name of the provider.

Return
Mac!	the new Mac object.

Exceptions
java.security.NoSuchAlgorithmException	if a MacSpi implementation for the specified algorithm is not available from the specified provider.
java.security.NoSuchProviderException	if the specified provider is not registered in the security provider list.
java.lang.IllegalArgumentException	if the provider is null or empty.

See Also

• java.security.Provider

getInstance

Added in API level 1

static fun getInstance(
    algorithm: String!, 
    provider: Provider!
): Mac!

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	String!: the standard name of the requested MAC algorithm. See the Mac section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
provider	Provider!: the provider.

Return
Mac!	the new Mac object.

Exceptions
java.security.NoSuchAlgorithmException	if a MacSpi implementation for the specified algorithm is not available from the specified Provider object.
java.lang.IllegalArgumentException	if the provider is null.

See Also

• java.security.Provider

getMacLength

Added in API level 1

fun getMacLength(): Int

Returns the length of the MAC in bytes.

Return
Int	the MAC length in bytes.

getProvider

Added in API level 1

fun getProvider(): Provider!

Returns the provider of this Mac object.

Return
Provider!	the provider of this Mac object.

init

Added in API level 1

fun init(key: Key!): Unit

Initializes this Mac object with the given key.

Parameters
key	Key!: the key.

Exceptions
java.security.InvalidKeyException	if the given key is inappropriate for initializing this MAC.

init

Added in API level 1

fun init(
    key: Key!, 
    params: AlgorithmParameterSpec!
): Unit

Initializes this Mac object with the given key and algorithm parameters.

Parameters
key	Key!: the key.
params	AlgorithmParameterSpec!: the algorithm parameters.

Exceptions
java.security.InvalidKeyException	if the given key is inappropriate for initializing this MAC.
java.security.InvalidAlgorithmParameterException	if the given algorithm parameters are inappropriate for this MAC.

reset

Added in API level 1

fun reset(): Unit

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).

update

Added in API level 1

fun update(input: Byte): Unit

Processes the given byte.

Parameters
input	Byte: the input byte to be processed.

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.

update

Added in API level 1

fun update(input: ByteArray!): Unit

Processes the given array of bytes.

Parameters
input	ByteArray!: the array of bytes to be processed.

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.

update

Added in API level 1

fun update(
    input: ByteArray!, 
    offset: Int, 
    len: Int
): Unit

Processes the first len bytes in input, starting at offset inclusive.

Parameters
input	ByteArray!: the input buffer.
offset	Int: the offset in input where the input starts.
len	Int: the number of bytes to process.

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.

update

Added in API level 1

fun update(input: ByteBuffer!): Unit

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	ByteBuffer!: the ByteBuffer

Exceptions
java.lang.IllegalStateException	if this Mac has not been initialized.