Package edu.fiu.adwise.homomorphic_encryption.elgamal

Class ElGamalKeyPairGenerator

java.lang.Object

java.security.KeyPairGeneratorSpi

edu.fiu.adwise.homomorphic_encryption.elgamal.ElGamalKeyPairGenerator

All Implemented Interfaces:

CipherConstants

public class ElGamalKeyPairGenerator
extends KeyPairGeneratorSpi
implements CipherConstants

This class is responsible for generating ElGamal key pairs. It supports both additive and multiplicative modes of the ElGamal cryptosystem.

Field Summary

Fields inherited from interface edu.fiu.adwise.homomorphic_encryption.misc.CipherConstants

BILLION, CERTAINTY, EIGHT, FIELD_SIZE, FIVE, FOUR, KEY_SIZE, NEG_ONE, rnd, THREE, TWO

Constructor Summary

Constructors

Constructor	Description
ElGamalKeyPairGenerator(boolean additive)	Constructs an ElGamalKeyPairGenerator.

Method Summary

Modifier and Type	Method	Description
KeyPair	generateKeyPair()	Generates an ElGamal key pair.
static BigInteger	getPrime(int nb_bits, Random prg)	Return a prime p = 2 * p' + 1
void	initialize(int key_size, SecureRandom random)	Initializes the key pair generator with the specified key size and random number generator.

Methods inherited from class java.security.KeyPairGeneratorSpi

initialize

Methods inherited from class java.lang.Object

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

Constructor Details

ElGamalKeyPairGenerator

public ElGamalKeyPairGenerator(boolean additive)

Constructs an ElGamalKeyPairGenerator.

Parameters:

additive - Specifies whether the key pair supports additive operations.

Method Details

initialize

public void initialize(int key_size,
 SecureRandom random)

Initializes the key pair generator with the specified key size and random number generator.

Specified by:

initialize in class KeyPairGeneratorSpi

Parameters:

key_size - The size of the key to generate (in bits).

random - The secure random number generator to use.

Throws:

IllegalArgumentException - If the key size is less than half of the default key size.

generateKeyPair

public KeyPair generateKeyPair()

Generates an ElGamal key pair.

Specified by:

generateKeyPair in class KeyPairGeneratorSpi

Returns:

A KeyPair containing the public and private keys.

getPrime

public static BigInteger getPrime(int nb_bits,
 Random prg)

Return a prime p = 2 * p' + 1

Parameters:

nb_bits - is the prime representation

prg - random

Returns:

p