Class DhAlgorithm

java.lang.Object

zeroecho.core.CryptoAlgorithm

zeroecho.core.alg.AbstractCryptoAlgorithm

zeroecho.core.alg.dh.DhAlgorithm

public final class DhAlgorithm
extends AbstractCryptoAlgorithm

Diffie-Hellman algorithm registration for use in the pluggable cryptography catalog.

This class registers a Diffie-Hellman (DH) algorithm under the identifier "DH" with sane defaults and JCA compatibility. It declares the algorithm’s capabilities, default parameters, and key builders so that higher layers can use DH for key agreement in a consistent and type-safe way.

Features

• Algorithm identifier and display name: "DH".
• Agreement capability producing AgreementContext instances backed by the JCA algorithm name "DiffieHellman".
• Default parameter specification: DhSpec.ffdhe2048().
• Asymmetric key builder for DhSpec-based key pair generation via DhKeyGenBuilder.
• Support for importing keys from DhPublicKeySpec and DhPrivateKeySpec using standard JCA key factories.

Thread-safety

Instances of DhAlgorithm are immutable after construction. They are typically created once at application startup and safely reused across threads as shared registrations in a CryptoCatalog.

Usage example

// Create and register the algorithm
DhAlgorithm dh = new DhAlgorithm();
CryptoCatalog catalog = CryptoCatalog.load();

// Create a DH spec (or rely on the default ffdhe2048)
DhSpec spec = DhSpec.ffdhe3072();

// Generate a key pair using the registered builder
KeyPair kp = session.keyBuilders().asymmetric().generateKeyPair("DH", spec);

// Obtain an agreement context for DH key agreement
AgreementContext ctx = session.createContext("DH", KeyUsage.AGREEMENT, kp.getPrivate(), spec);

// Use the context with a peer public key to derive a shared secret
ctx.setPeerPublic(peerPublicKey);
byte[] secret = ctx.deriveSecret();

Since:

1.0

See Also:

• AlgorithmFamily
• KeyUsage
• AgreementContext
• DhSpec
• DhKeyGenBuilder
• AbstractCryptoAlgorithm

Constructor Summary

Constructors

Constructor	Description
DhAlgorithm()	Creates a Diffie-Hellman algorithm registration with standard defaults.

Method Summary

Modifier and Type	Method	Description
List<ParameterSetDescriptor<? extends AlgorithmKeySpec>>	parameterSets()	Returns the discoverable parameter sets (or parameterized templates) supported by this algorithm.

Methods inherited from class AbstractCryptoAlgorithm

capability

Methods inherited from class CryptoAlgorithm

addCapability, asymmetricKeyPairGenerator, bindContext, createContext, displayName, id, keyOperations, listCapabilities, priority, privateKeyImporter, providerName, publicKeyImporter, registerAsymmetricKeyPairGenerator, registerPrivateKeyImporter, registerPublicKeyImporter, registerSymmetricKeyGenerator, registerSymmetricKeyImporter, requiresStatefulSigning, roles, supports, symmetricKeyGenerator, symmetricKeyImporter

Methods inherited from class Object

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

Constructor Details

DhAlgorithm

public DhAlgorithm()

Creates a Diffie-Hellman algorithm registration with standard defaults.

This constructor:

• Registers the algorithm under the identifier "DH" and display name "DH".
• Declares an AlgorithmFamily.AGREEMENT capability for KeyUsage.AGREEMENT, producing GenericJcaAgreementContext instances bound to the JCA name "DiffieHellman".
• Sets DhSpec.ffdhe2048() as the default parameter specification.
• Registers DhKeyGenBuilder as the asymmetric key builder for DhSpec.
• Registers asymmetric key builders for importing keys via DhPublicKeySpec and DhPrivateKeySpec using JCA KeyFactory.

Method Details

parameterSets

public List<ParameterSetDescriptor<? extends AlgorithmKeySpec>> parameterSets()

Description copied from class: CryptoAlgorithm

Returns the discoverable parameter sets (or parameterized templates) supported by this algorithm.

Callers (UIs, provisioning tools, policy engines) use this list to present users with valid, named key-generation options without prior knowledge of the concrete algorithm. Each entry is either a pre-built ParameterSetDescriptor.Concrete (ready spec) or a ParameterSetDescriptor.Template (user-supplied arguments produce the spec).

The default implementation returns an empty list. Algorithms with finite, enumerable parameter sets should override this method. Overrides must return immutable lists in stable order, with unique nonblank descriptor identifiers. Registry loading validates a snapshot; external providers remain responsible for maintaining the contract on subsequent calls. Implementations may use ParameterSetDescriptor.snapshot(List) to validate and copy their list.

Overrides:

parameterSets in class CryptoAlgorithm

Returns:

immutable list of parameter set descriptors; never null