HmacSHA256

java.lang.Object
- javax.crypto.MacSpi
- - com.ibm.crypto.fips.provider.HmacSHA256

All Implemented Interfaces:

java.lang.Cloneable
```
public final class HmacSHA256
extends javax.crypto.MacSpi
implements java.lang.Cloneable
```
This is an implementation of the HMAC-SHA256 algorithm.

Constructor Summary

Constructors
Constructor and Description

HmacSHA256()
Standard constructor, creates a new HmacSHA256 instance.

Constructors
Constructor and Description
`HmacSHA256()` Standard constructor, creates a new HmacSHA256 instance.

Method Summary

Methods
Modifier and Type	Method and Description
`java.lang.Object`	`clone()`
`protected byte[]`	`engineDoFinal()` Completes the HMAC computation and resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
`protected int`	`engineGetMacLength()` Returns the length of the HMAC in bytes.
`protected void`	`engineInit(java.security.Key key, java.security.spec.AlgorithmParameterSpec params)` Initializes the HMAC with the given secret key and algorithm parameters.
`protected void`	`engineReset()` Resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
`protected void`	`engineUpdate(byte input)` Processes the given byte.
`protected void`	`engineUpdate(byte[] input, int offset, int len)` Processes the first `len` bytes in `input`, starting at `offset`.
`protected void`	`finalize()` This function zeroizes the key so that it isn't in memory when GC is done.
`java.lang.Object`	`internalClone()`
`protected byte[]`	`internalDoFinal()` Completes the HMAC computation and resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
`protected int`	`internalGetMacLength()` Returns the length of the HMAC in bytes.
`protected void`	`internalInit(java.security.Key key, java.security.spec.AlgorithmParameterSpec params)` Initializes the HMAC with the given secret key and algorithm parameters.
`protected void`	`internalReset()` Resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
`protected void`	`internalUpdate(byte input)` Processes the given byte.
`protected void`	`internalUpdate(byte[] input, int offset, int len)` Processes the first `len` bytes in `input`, starting at `offset`.
`void`	`zeroize()` This function zeroizes the key so that it isn't in memory

Methods inherited from class javax.crypto.MacSpi
engineUpdate

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - HmacSHA256
```
public HmacSHA256()
           throws java.security.NoSuchAlgorithmException
```
    Standard constructor, creates a new HmacSHA256 instance. Verify the JCE framework in the constructor.
    
    Throws:
    
    java.lang.SecurityException - if fails to verify the JCE framework.
    
    java.security.NoSuchAlgorithmException
- Method Detail
  - engineGetMacLength
```
protected int engineGetMacLength()
```
    Returns the length of the HMAC in bytes.
    
    Specified by:
    
    engineGetMacLength in class javax.crypto.MacSpi
    
    Returns:
    the HMAC length in bytes.
    
    Throws:
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalGetMacLength
```
protected int internalGetMacLength()
```
    Returns the length of the HMAC in bytes.
    
    Returns:
    the HMAC length in bytes.
  - engineInit
```
protected void engineInit(java.security.Key key,
              java.security.spec.AlgorithmParameterSpec params)
                   throws java.security.InvalidKeyException,
                          java.security.InvalidAlgorithmParameterException
```
    Initializes the HMAC with the given secret key and algorithm parameters.
    
    Specified by:
    
    engineInit in class javax.crypto.MacSpi
    
    Parameters:
    key - the secret key.
    params - the algorithm parameters.
    
    Throws:
    
    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.
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalInit
```
protected void internalInit(java.security.Key key,
                java.security.spec.AlgorithmParameterSpec params)
                     throws java.security.InvalidKeyException,
                            java.security.InvalidAlgorithmParameterException
```
    Initializes the HMAC with the given secret key and algorithm parameters.
    
    Parameters:
    key - the secret key.
    params - the algorithm parameters.
    
    Throws:
    
    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.
  - engineUpdate
```
protected void engineUpdate(byte input)
```
    Processes the given byte.
    
    Specified by:
    
    engineUpdate in class javax.crypto.MacSpi
    
    Parameters:
    input - the input byte to be processed.
    
    Throws:
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalUpdate
```
protected void internalUpdate(byte input)
```
    Processes the given byte.
    
    Parameters:
    input - the input byte to be processed.
  - engineUpdate
```
protected void engineUpdate(byte[] input,
                int offset,
                int len)
```
    Processes the first len bytes in input, starting at offset.
    
    Specified by:
    
    engineUpdate in class javax.crypto.MacSpi
    
    Parameters:
    input - the input buffer.
    offset - the offset in input where the input starts.
    len - the number of bytes to process.
    
    Throws:
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalUpdate
```
protected void internalUpdate(byte[] input,
                  int offset,
                  int len)
```
    Processes the first len bytes in input, starting at offset.
    
    Parameters:
    input - the input buffer.
    offset - the offset in input where the input starts.
    len - the number of bytes to process.
  - engineDoFinal
```
protected byte[] engineDoFinal()
```
    Completes the HMAC computation and resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
    
    Specified by:
    
    engineDoFinal in class javax.crypto.MacSpi
    
    Returns:
    the HMAC result.
    
    Throws:
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalDoFinal
```
protected byte[] internalDoFinal()
```
    Completes the HMAC computation and resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
    
    Returns:
    the HMAC result.
  - engineReset
```
protected void engineReset()
```
    Resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
    
    Specified by:
    
    engineReset in class javax.crypto.MacSpi
    
    Throws:
    
    FIPSRuntimeException - if SelfTest.isFipsRunnable returns false.
  - internalReset
```
protected void internalReset()
```
    Resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
  - clone
```
public java.lang.Object clone()
```
    Overrides:
    
    clone in class javax.crypto.MacSpi
  - internalClone
```
public java.lang.Object internalClone()
```
  - zeroize
```
public void zeroize()
```
    This function zeroizes the key so that it isn't in memory
  - finalize
```
protected void finalize()
```
    This function zeroizes the key so that it isn't in memory when GC is done.
    
    Overrides:
    
    finalize in class java.lang.Object

Methods inherited from class javax.crypto.MacSpi

Methods inherited from class java.lang.Object

HmacSHA256

engineGetMacLength

internalGetMacLength

engineInit

internalInit

engineUpdate

internalUpdate

engineUpdate

internalUpdate

engineDoFinal

internalDoFinal

engineReset

internalReset

clone

internalClone

zeroize

finalize