SHA256Generator (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- net.i2p.crypto.SHA256Generator

```
public final class SHA256Generator
extends Object
```
Defines a wrapper for SHA-256 operation. As of release 0.8.7, uses java.security.MessageDigest by default. As of release 0.9.25, uses only MessageDigest. GNU-Crypto gnu.crypto.hash.Sha256Standalone is removed as of 0.9.28.

Constructor Summary
Constructors
Constructor and Description
SHA256Generator(I2PAppContext context)
Unused.

Constructors
Constructor and Description
`SHA256Generator(I2PAppContext context)` Unused.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`MessageDigest`	`acquire()` Get a MessageDigest instance from the pool, for uses where the one-shot calculateHash() would require copying the data.
`Hash`	`calculateHash(byte[] source)` Calculate the SHA-256 hash of the source and cache the result.
`Hash`	`calculateHash(byte[] source, int start, int len)` Calculate the hash and cache the result.
`void`	`calculateHash(byte[] source, int start, int len, byte[] out, int outOffset)` Use this if you only need the data, not a Hash object.
`static MessageDigest`	`getDigestInstance()` Return a new MessageDigest from the system libs.
`static SHA256Generator`	`getInstance()` Instance.
`static void`	`main(String[] args)` main.
`void`	`release(MessageDigest digest)` Release a digest back to the pool

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

- Constructor Detail
  - SHA256Generator
```
public SHA256Generator(I2PAppContext context)
```
    Unused.
    Parameters:
    context - unused
- Method Detail
  - acquire
```
public MessageDigest acquire()
```
    Get a MessageDigest instance from the pool, for uses where the one-shot calculateHash() would require copying the data. Return the instance via release() when done.
    Returns:
    a MessageDigest instance
  - calculateHash
```
public final Hash calculateHash(byte[] source)
```
    Calculate the SHA-256 hash of the source and cache the result.
    Parameters:
    source - what to hash
    Returns:
    hash of the source
  - calculateHash
```
public final Hash calculateHash(byte[] source,
                                int start,
                                int len)
```
    Calculate the hash and cache the result.
    Parameters:
    source - what to hash
    start - the starting offset
    len - the length to hash
    Returns:
    the hash
  - calculateHash
```
public final void calculateHash(byte[] source,
                                int start,
                                int len,
                                byte[] out,
                                int outOffset)
```
    Use this if you only need the data, not a Hash object. Does not cache.
    Parameters:
    out - needs 32 bytes starting at outOffset
  - getDigestInstance
```
public static MessageDigest getDigestInstance()
```
    Return a new MessageDigest from the system libs.
    Returns:
    the digest instance
  - getInstance
```
public static final SHA256Generator getInstance()
```
    Instance.
    Returns:
    the instance
  - main
```
public static void main(String[] args)
```
    main.
  - release
```
public void release(MessageDigest digest)
```
    Release a digest back to the pool
    Parameters:
    digest - must be SHA-256

Class SHA256Generator

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SHA256Generator

Method Detail

acquire

calculateHash

calculateHash

calculateHash

getDigestInstance

getInstance

main

release