org.kocakosm.jblake2

Class Blake2b

java.lang.Object

org.kocakosm.jblake2.Blake2b

public final class Blake2b
extends Object

The BLAKE2b digest algorithm. Instances of this class are not thread safe. This class implements the BLAKE2b algorithm as specified in RFC 7693. The original paper defines some additional variants with features such as salting, personalization and tree hashing. These features are considered optional and not covered by the RFC. BLAKE2b can be directly keyed, making it functionally equivalent to a Message Authentication Code (it does not require a special construction like HMAC).

Author:

Osman Koçak

See Also:

blake2.net, RFC 7693

Constructor Summary

Constructors

Constructor and Description
Blake2b(byte[] key, int digestLength) Creates a new keyed Blake2b instance.
Blake2b(int digestLength) Creates a new unkeyed Blake2b instance.

Method Summary

Methods

Modifier and Type	Method and Description
void	burn() Erases the key and resets the digest, making this instance functionally equivalent to a newly created unkeyed digest.
Blake2b	copy() Returns a copy of this object.
byte[]	digest() Completes the hash computation.
byte[]	digest(byte... input) Performs a final update on the digest using the specified array of bytes, then completes the digest computation.
byte[]	digest(byte[] input, int off, int len) Performs a final update on the digest using the specified data bytes, then completes the digest computation.
int	length() Returns the digest's length (in bytes).
Blake2b	reset() Resets the digest.
Blake2b	update(byte... input) Updates the digest using the given array of bytes.
Blake2b	update(byte input) Updates the digest using the given byte.
Blake2b	update(byte[] input, int off, int len) Updates the digest using the specified number of bytes from the given array, starting at the specified offset.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Blake2b

public Blake2b(int digestLength)

Creates a new unkeyed Blake2b instance.

Parameters:

digestLength - the desired digest's length (in bytes).

Throws:

IllegalArgumentException - if digestLength is not in the [1, 64] range.

Blake2b

public Blake2b(byte[] key,
       int digestLength)

Creates a new keyed Blake2b instance. If the key is empty, then the created instance is equivalent to an unkeyed digest. The given key can be safely erased from memory after this constructor has been called.

Parameters:

key - the key to use.

digestLength - the desired digest's length (in bytes).

Throws:

NullPointerException - if key is null.

IllegalArgumentException - if key's length is greater than 64 or if digestLength is not in the [1, 64] range.

Method Detail

burn

public void burn()

Erases the key and resets the digest, making this instance functionally equivalent to a newly created unkeyed digest. If this instance is already unkeyed, calling this method has no other effect than resetting the digest.

copy

public Blake2b copy()

Returns a copy of this object.

Returns:

a copy of this object.

length

public int length()

Returns the digest's length (in bytes).

Returns:

the digest's length (in bytes).

reset

public Blake2b reset()

Resets the digest. Note that this does not erase the key.

Returns:

this object.

update

public Blake2b update(byte input)

Updates the digest using the given byte.

Parameters:

input - the byte with which to update the digest.

Returns:

this object.

update

public Blake2b update(byte... input)

Updates the digest using the given array of bytes.

Parameters:

input - the array of bytes with which to update the digest.

Returns:

this object.

Throws:

NullPointerException - if input is null.

update

public Blake2b update(byte[] input,
             int off,
             int len)

Updates the digest using the specified number of bytes from the given array, starting at the specified offset.

Parameters:

input - the array of bytes.

off - the offset to start from in the array, inclusive.

len - the number of bytes to use, starting at off.

Returns:

this object.

Throws:

NullPointerException - if input is null.

IndexOutOfBoundsException - if off is negative or if len is negative or if off + len is greater than input's length.

digest

public byte[] digest(byte... input)

Performs a final update on the digest using the specified array of bytes, then completes the digest computation. That is, this method first calls update(byte...), passing the input array to the update method, then calls digest(). Note that the digest is reset after this call is made.

Parameters:

input - the array of bytes with which to update the digest before completing its computation.

Returns:

the resulting digest.

Throws:

NullPointerException - if input is null.

digest

public byte[] digest(byte[] input,
            int off,
            int len)

Performs a final update on the digest using the specified data bytes, then completes the digest computation. That is, this method first calls update(byte[], int, int), passing the input array to the update method, then calls digest(). Note that the digest is reset after this call is made.

Parameters:

input - the array of bytes.

off - the offset to start from in the array, inclusive.

len - the number of bytes to use, starting at off.

Returns:

the resulting digest.

Throws:

NullPointerException - if input is null.

IndexOutOfBoundsException - if off is negative or if len is negative or if off + len is greater than input's length.

digest

public byte[] digest()

Completes the hash computation. Note that the digest is reset after this call is made.

Returns:

the resulting digest.