GordianKnot Digests

Overview

Digests are supported via the GordianDigestFactory interface.

GordianKnot supports most Digests available from BouncyCastle plus some additional algorithms.

JCA provides a subset of available algorithms as indicated

Digests

A digest is created by specifying a GordianDigestSpec which comprises the digestType/OutputLength plus StateLength if applicable. The digest can be used in much the same way as a JCA Digest, allowing reset, update and finalise methods.

Sample

/* Access factory */
final GordianFactory myBaseFactory = GordianGenerator.createFactory();
final GordianDigestFactory myDigestFactory = myBaseFactory.getDigestFactory();

/* Create digest */
final GordianDigestSpec mySpec = GordianDigestSpecBuilder.sha2(GordianLength.LEN_256);
final GordianDigest myDigest = myDigestFactory.createDigest(mySpec);

/* Calculate digest */
final byte[] myMessage = ...
myDigest.update(myMessage);
final byte[] myResult = myDigest.finish();
                    

Extensible Output functions

Some digests can operate as extensible output functions, although the functionality is not available in JCA.

The **GordianDigestSpec** for the digest will indicate whether the digest supports Xof or not via the **isXof()** call. If the digest supports Xof then the digest will present the **GordianXof** interface

Sample

Algorithms

The following algorithms are supported.