Class ElgamalPublicKeySpec

java.lang.Object

zeroecho.core.alg.elgamal.ElgamalPublicKeySpec

All Implemented Interfaces:

AlgorithmKeySpec

public final class ElgamalPublicKeySpec
extends Object
implements AlgorithmKeySpec

ElGamal Public Key Specification

Wrapper for an X.509-encoded ElGamal public key.

This specification serves as the input to key-import routines, providing a portable representation of public key material. The encoding format is assumed to be X.509 DER, as produced by standard JCA/JCE providers.

Contents

• encoded() returns a defensive copy of the raw X.509 bytes.
• marshal(ElgamalPublicKeySpec) encodes the key into a PairSeq structure for transport or logging.
• unmarshal(PairSeq) reconstructs the spec from a marshalled representation.

Usage

// Import from X.509 DER
byte[] der = Files.readAllBytes(Path.of("elgamal-pub.der"));
ElgamalPublicKeySpec spec = new ElgamalPublicKeySpec(der);
PublicKey pub = algo.publicKeyImporter(ElgamalPublicKeySpec.class).importPublic(spec);

// Marshal for serialization
PairSeq ps = ElgamalPublicKeySpec.marshal(spec);

// Unmarshal back
ElgamalPublicKeySpec restored = ElgamalPublicKeySpec.unmarshal(ps);

Security considerations

• Public keys are not secret, but they must be bound to the correct parameters (modulus and generator) to avoid substitution attacks.
• Always validate public key encoding against trusted parameter sets before using in protocols.

Thread-safety

Instances are immutable and safe to share between threads.

Since:

1.0

Constructor Summary

Constructors

Constructor	Description
ElgamalPublicKeySpec(byte[] x509)	Constructs a new public key spec from X.509-encoded bytes.

Method Summary

Modifier and Type	Method	Description
byte[]	encoded()	Returns a defensive copy of the X.509-encoded public key.
static PairSeq	marshal(ElgamalPublicKeySpec spec)	Serializes this spec into a PairSeq.
static ElgamalPublicKeySpec	unmarshal(PairSeq p)	Parses a PairSeq and reconstructs an ElgamalPublicKeySpec.

Methods inherited from class Object

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

Constructor Details

ElgamalPublicKeySpec

public ElgamalPublicKeySpec(byte[] x509)

Constructs a new public key spec from X.509-encoded bytes.

Parameters:

x509 - X.509 DER encoding of the public key; must not be null

Method Details

encoded

public byte[] encoded()

Returns a defensive copy of the X.509-encoded public key.

Returns:

X.509 DER encoding

marshal

public static PairSeq marshal(ElgamalPublicKeySpec spec)

Serializes this spec into a PairSeq.

The output includes:

• type = "ELGAMAL-PUB"
• x509.b64 = Base64 encoding of the DER bytes (without padding)

Parameters:

spec - ElGamal public key spec

Returns:

marshalled key as PairSeq

unmarshal

public static ElgamalPublicKeySpec unmarshal(PairSeq p)

Parses a PairSeq and reconstructs an ElgamalPublicKeySpec.

Parameters:

p - encoded pair sequence

Returns:

new public key spec

Throws:

IllegalArgumentException - if required field x509.b64 is missing