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 |
Summary
| Protected constructors | |
|---|---|
|
Creates a MAC object. |
|
| Public methods | |
|---|---|
| Any |
clone()Returns a clone if the provider implementation is cloneable. |
| ByteArray! |
doFinal()Finishes the MAC operation. |
| Unit |
Finishes the MAC operation. |
| ByteArray! |
Processes the given array of bytes and finishes the MAC operation. |
| String! |
Returns the algorithm name of this |
| static Mac! |
getInstance(algorithm: String!)Returns a |
| static Mac! |
getInstance(algorithm: String!, provider: String!)Returns a |
| static Mac! |
getInstance(algorithm: String!, provider: Provider!)Returns a |
| Int |
Returns the length of the MAC in bytes. |
| Provider! |
Returns the provider of this |
| Unit |
Initializes this |
| Unit |
init(key: Key!, params: AlgorithmParameterSpec!)Initializes this |
| Unit |
reset()Resets this |
| Unit |
Processes the given byte. |
| Unit |
Processes the given array of bytes. |
| Unit |
Processes the first |
| Unit |
update(input: ByteBuffer!)Processes |
Protected constructors
Mac
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
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
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
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
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
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
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
getInstance
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
getInstance
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
getMacLength
fun getMacLength(): Int
Returns the length of the MAC in bytes.
| Return | |
|---|---|
Int |
the MAC length in bytes. |
getProvider
fun getProvider(): Provider!
Returns the provider of this Mac object.
| Return | |
|---|---|
Provider! |
the provider of this Mac object. |
init
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
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
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
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
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
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
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. |