Class AbstractEncodedPublicKeyBuilder<S extends AlgorithmKeySpec>

java.lang.Object

zeroecho.core.alg.common.eddsa.AbstractEncodedPublicKeyBuilder<S>

Type Parameters:

S - the algorithm-specific key specification carrying X.509 data

All Implemented Interfaces:

PublicKeyImporter<S>

Direct Known Subclasses:

Ed25519PublicKeyBuilder, Ed448PublicKeyBuilder

public abstract class AbstractEncodedPublicKeyBuilder<S extends AlgorithmKeySpec>
extends Object
implements PublicKeyImporter<S>

Abstract EdDSA Encoded Public Key Builder

Base class for reconstructing EdDSA public keys (e.g., Ed25519, Ed448) from X.509-encoded specifications.

Unlike AbstractEdDSAKeyGenBuilder, which generates new key pairs, and AbstractEncodedPrivateKeyBuilder, which restores private keys, this class focuses exclusively on importing existing public keys from their encoded form. Key pair generation and private key import are intentionally unsupported here.

Responsibilities

• Define jcaKeyFactoryAlg() to return the canonical JCA algorithm name (e.g., "Ed25519", "Ed448").
• Define encodedX509(AlgorithmKeySpec) to extract the raw X.509-encoded public key bytes from the given spec.
• Provide an importPublic(AlgorithmKeySpec) implementation that rebuilds a PublicKey using KeyFactory and the encoded X.509 material.

Thread-safety

Stateless and safe for concurrent use. Each call to importPublic(AlgorithmKeySpec) creates a new KeyFactory.

Since:

1.0

Constructor Summary

Constructors

Constructor	Description
AbstractEncodedPublicKeyBuilder()	Creates a stateless encoded-public-key importer base.

Method Summary

Modifier and Type	Method	Description
protected abstract byte[]	encodedX509(S spec)	Extracts the raw X.509-encoded public key bytes from the given spec.
PublicKey	importPublic(S spec)	Imports an EdDSA public key from its X.509-encoded form.
protected abstract String	jcaKeyFactoryAlg()	Returns the canonical JCA algorithm identifier used by KeyFactory.getInstance(String).

Methods inherited from class Object

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

Constructor Details

AbstractEncodedPublicKeyBuilder

public AbstractEncodedPublicKeyBuilder()

Creates a stateless encoded-public-key importer base.

Method Details

jcaKeyFactoryAlg

protected abstract String jcaKeyFactoryAlg()

Returns the canonical JCA algorithm identifier used by KeyFactory.getInstance(String).

Must be one of the algorithm names recognized by the JDK (e.g., "Ed25519", "Ed448").

Returns:

the JCA algorithm identifier string

encodedX509

protected abstract byte[] encodedX509(S spec)

Extracts the raw X.509-encoded public key bytes from the given spec.

Subclasses must implement this to pull the encoded material from their AlgorithmKeySpec representation.

Parameters:

spec - algorithm-specific key specification

Returns:

X.509-encoded public key bytes

importPublic

public PublicKey importPublic(S spec)
                       throws GeneralSecurityException

Imports an EdDSA public key from its X.509-encoded form.

This method uses KeyFactory initialized with the algorithm returned by jcaKeyFactoryAlg() to parse the bytes provided by encodedX509(AlgorithmKeySpec).

Specified by:

importPublic in interface PublicKeyImporter<S extends AlgorithmKeySpec>

Parameters:

spec - algorithm-specific key specification containing X.509 bytes

Returns:

a reconstructed PublicKey instance

Throws:

GeneralSecurityException - if the key material is invalid or the JCA provider does not support the algorithm