Package edu.fiu.adwise.homomorphic_encryption.socialistmillionaire

Class alice_elgamal

java.lang.Object

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.socialist_millionaires

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.alice

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.alice_veugen

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.alice_elgamal

All Implemented Interfaces:

CipherConstants, alice_interface

public class alice_elgamal
extends alice_veugen

Represents Alice's implementation of the ElGamal protocol for secure computation. This class extends the `alice_veugen` class and provides methods for performing arithmetic operations and secure comparisons using the ElGamal encryption scheme.

Field Summary

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

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

Constructor Summary

Constructors

Constructor	Description
alice_elgamal()	Constructs an instance of `alice_elgamal`.

Method Summary

Modifier and Type	Method	Description
ElGamal_Ciphertext	addition(ElGamal_Ciphertext x, ElGamal_Ciphertext y)	Performs addition on two encrypted values from alice.
ElGamal_Ciphertext	division(ElGamal_Ciphertext x, long d)	Performs division on an encrypted value x from alice by a given divisor from bob.
List<ElGamal_Ciphertext>	getKMin(List<ElGamal_Ciphertext> input, int k)	Retrieves the k smallest encrypted values from a list.
ElGamal_Ciphertext	multiplication(ElGamal_Ciphertext x, ElGamal_Ciphertext y)	Performs multiplication on two encrypted values.
boolean	Protocol4(ElGamal_Ciphertext x, ElGamal_Ciphertext y)	See the paper Correction to "Improving the DGK comparison protocol", this implements Protocol 3.

Methods inherited from class edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.alice_veugen

Protocol1, Protocol2

Methods inherited from class edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.alice

division, encrypted_equals, encrypted_xor, getKValues, getKValues, multiplication, private_equals, receivePublicKeys, set_dgk_private_key, set_socket

Methods inherited from class edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.socialist_millionaires

get_bytes_sent, getDGKPublicKey, getElGamalPublicKey, getPaillierPublicKey, isDGK, readBoolean, readInt, readObject, setDGKMode, setDGKPublicKey, setElGamalPublicKey, setPaillierPublicKey, writeBoolean, writeInt, writeObject

Methods inherited from class java.lang.Object

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

Constructor Details

alice_elgamal

public alice_elgamal()

Constructs an instance of `alice_elgamal`.

Method Details

addition

public ElGamal_Ciphertext addition(ElGamal_Ciphertext x,
 ElGamal_Ciphertext y)
                            throws IOException,
ClassNotFoundException,
IllegalArgumentException

Performs addition on two encrypted values from alice.

Parameters:

x - the first encrypted value.

y - the second encrypted value.

Returns:

the encrypted result of the addition.

Throws:

IOException - if an I/O error occurs during communication.

ClassNotFoundException - if a class cannot be found during deserialization.

IllegalArgumentException - if invalid arguments are provided.

multiplication

public ElGamal_Ciphertext multiplication(ElGamal_Ciphertext x,
 ElGamal_Ciphertext y)
                                  throws IOException,
ClassNotFoundException,
IllegalArgumentException

Performs multiplication on two encrypted values. Use a multi-party protocol if alice provides two additive El-Gamal encrypted values

Parameters:

x - the first encrypted value.

y - the second encrypted value.

Returns:

the encrypted result of the multiplication.

Throws:

IOException - if an I/O error occurs during communication.

ClassNotFoundException - if a class cannot be found during deserialization.

IllegalArgumentException - if invalid arguments are provided.

division

public ElGamal_Ciphertext division(ElGamal_Ciphertext x,
 long d)
                            throws IOException,
ClassNotFoundException,
IllegalArgumentException,
HomomorphicException

Performs division on an encrypted value x from alice by a given divisor from bob.

Parameters:

x - the encrypted value to divide.

d - the divisor.

Returns:

the encrypted result of the division.

Throws:

IOException - if an I/O error occurs during communication.

ClassNotFoundException - if a class cannot be found during deserialization.

IllegalArgumentException - if invalid arguments are provided.

HomomorphicException - if the ElGamal keys do not support additive operations.

Protocol4

public boolean Protocol4(ElGamal_Ciphertext x,
 ElGamal_Ciphertext y)
                  throws IOException,
ClassNotFoundException,
HomomorphicException

See the paper Correction to "Improving the DGK comparison protocol", this implements Protocol 3. This is an improved version of Protocol 1, initially created by DGK, see original bob class This executes a protocol comparing two encrypted ElGamal values

Parameters:

x - the first encrypted value.

y - the second encrypted value.

Returns:

true if x >= y, false otherwise.

Throws:

IOException - if an I/O error occurs during communication.

ClassNotFoundException - if a class cannot be found during deserialization.

HomomorphicException - if an error occurs during the protocol execution.

getKMin

public List<ElGamal_Ciphertext> getKMin(List<ElGamal_Ciphertext> input,
 int k)
                                 throws ClassNotFoundException,
IOException,
IllegalArgumentException,
HomomorphicException

Retrieves the k smallest encrypted values from a list.

Parameters:

input - the list of encrypted values.

k - the number of smallest values to retrieve.

Returns:

a list of the k smallest encrypted values.

Throws:

ClassNotFoundException - if a class cannot be found during deserialization.

IOException - if an I/O error occurs during communication.

IllegalArgumentException - if the value of k is invalid.

HomomorphicException - if an error occurs during the sorting process.