org.spongycastle.crypto.digests

Class Blake2bDigest

java.lang.Object

org.spongycastle.crypto.digests.Blake2bDigest

All Implemented Interfaces:

Digest, ExtendedDigest

public class Blake2bDigest
extends java.lang.Object
implements ExtendedDigest

Implementation of the cryptographic hash function Blakbe2b.

Blake2b offers a built-in keying mechanism to be used directly for authentication ("Prefix-MAC") rather than a HMAC construction.

Blake2b offers a built-in support for a salt for randomized hashing and a personal string for defining a unique hash function for each application.

BLAKE2b is optimized for 64-bit platforms and produces digests of any size between 1 and 64 bytes.

Constructor Summary

Constructors

Constructor and Description
Blake2bDigest()
Blake2bDigest(Blake2bDigest digest)
Blake2bDigest(byte[] key) Blake2b for authentication ("Prefix-MAC mode").
Blake2bDigest(byte[] key, int digestLength, byte[] salt, byte[] personalization) Blake2b with key, required digest length (in bytes), salt and personalization.
Blake2bDigest(int digestSize) Basic sized constructor - size in bits.

Method Summary

Modifier and Type	Method and Description
void	clearKey() Overwrite the key if it is no longer used (zeroization)
void	clearSalt() Overwrite the salt (pepper) if it is secret and no longer used (zeroization)
int	doFinal(byte[] out, int outOffset) close the digest, producing the final digest value.
java.lang.String	getAlgorithmName() return the algorithm name
int	getByteLength() Return the size in bytes of the internal buffer the digest applies it's compression function to.
int	getDigestSize() return the size, in bytes, of the digest produced by this message digest.
void	reset() Reset the digest back to it's initial state.
void	update(byte b) update the message digest with a single byte.
void	update(byte[] message, int offset, int len) update the message digest with a block of bytes.

Methods inherited from class java.lang.Object

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

Constructor Detail

Blake2bDigest

public Blake2bDigest()

Blake2bDigest

public Blake2bDigest(Blake2bDigest digest)

Blake2bDigest

public Blake2bDigest(int digestSize)

Basic sized constructor - size in bits.

Parameters:

digestSize - size of the digest in bits

Blake2bDigest

public Blake2bDigest(byte[] key)

Blake2b for authentication ("Prefix-MAC mode"). After calling the doFinal() method, the key will remain to be used for further computations of this instance. The key can be overwritten using the clearKey() method.

Parameters:

key - A key up to 64 bytes or null

Blake2bDigest

public Blake2bDigest(byte[] key,
                     int digestLength,
                     byte[] salt,
                     byte[] personalization)

Blake2b with key, required digest length (in bytes), salt and personalization. After calling the doFinal() method, the key, the salt and the personal string will remain and might be used for further computations with this instance. The key can be overwritten using the clearKey() method, the salt (pepper) can be overwritten using the clearSalt() method.

Parameters:

key - A key up to 64 bytes or null

digestLength - from 1 up to 64 bytes

salt - 16 bytes or null

personalization - 16 bytes or null

Method Detail

update

public void update(byte b)

update the message digest with a single byte.

Specified by:

update in interface Digest

Parameters:

b - the input byte to be entered.

update

public void update(byte[] message,
                   int offset,
                   int len)

update the message digest with a block of bytes.

Specified by:

update in interface Digest

Parameters:

message - the byte array containing the data.

offset - the offset into the byte array where the data starts.

len - the length of the data.

doFinal

public int doFinal(byte[] out,
                   int outOffset)

close the digest, producing the final digest value. The doFinal call leaves the digest reset. Key, salt and personal string remain.

Specified by:

doFinal in interface Digest

Parameters:

out - the array the digest is to be copied into.

outOffset - the offset into the out array the digest is to start at.

reset

public void reset()

Reset the digest back to it's initial state. The key, the salt and the personal string will remain for further computations.

Specified by:

reset in interface Digest

getAlgorithmName

public java.lang.String getAlgorithmName()

return the algorithm name

Specified by:

getAlgorithmName in interface Digest

Returns:

the algorithm name

getDigestSize

public int getDigestSize()

return the size, in bytes, of the digest produced by this message digest.

Specified by:

getDigestSize in interface Digest

Returns:

the size, in bytes, of the digest produced by this message digest.

getByteLength

public int getByteLength()

Return the size in bytes of the internal buffer the digest applies it's compression function to.

Specified by:

getByteLength in interface ExtendedDigest

Returns:

byte length of the digests internal buffer.

clearKey

public void clearKey()

Overwrite the key if it is no longer used (zeroization)

clearSalt

public void clearSalt()

Overwrite the salt (pepper) if it is secret and no longer used (zeroization)