Package edu.fiu.adwise.homomorphic_encryption.socialistmillionaire

Class bob_elgamal

java.lang.Object

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.socialist_millionaires

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.bob

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.bob_veugen

edu.fiu.adwise.homomorphic_encryption.socialistmillionaire.bob_elgamal

All Implemented Interfaces:

CipherConstants, bob_interface

public class bob_elgamal
extends bob_veugen

Represents Bob's implementation of the multi-party protocols for secure computation with ElGamal cryptography. This class extends the `bob_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
bob_elgamal(KeyPair a, KeyPair b, KeyPair c)	Constructs a `bob_elgamal` instance with three key pairs.

Method Summary

Modifier and Type	Method	Description
void	addition(boolean addition)	Performs addition or subtraction to get the encrypted value of two blinded encrypted values
void	division(long divisor)	Performs division on an encrypted value from alice by a given divisor by Bob.
void	multiplication()	Performs multiplication on blinded encrypted values from alice.
boolean	Protocol2()	See the papers "Improving the DGK comparison protocol" and Correction to ”Improving the DGK comparison protocol” by Thjis Veugen, You can find these in the papers directory! Sorts a list of encrypted numbers using Protocol 4 (see the Veugen papers).
void	sort()	See the papers "Improving the DGK comparison protocol" and Correction to ”Improving the DGK comparison protocol” by Thjis Veugen, You can find these in the papers directory! Sorts a list of encrypted numbers using Protocol 4 (see the Veugen papers).

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

compute_delta_b, encrypt_bits, encrypted_equals, Protocol1, sendPublicKeys, 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

bob_elgamal

public bob_elgamal(KeyPair a,
 KeyPair b,
 KeyPair c)
            throws IllegalArgumentException

Constructs a `bob_elgamal` instance with three key pairs.

Parameters:

a - the first key pair (ElGamal or other encryption scheme).

b - the second key pair (ElGamal or other encryption scheme).

c - the third key pair (optional, e.g., ElGamal).

Throws:

IllegalArgumentException - if the provided key pairs are invalid or mismatched.

Method Details

addition

public void addition(boolean addition)
              throws IOException,
ClassNotFoundException,
IllegalArgumentException,
HomomorphicException

Performs addition or subtraction to get the encrypted value of two blinded encrypted values

Parameters:

addition - true for addition, false for subtraction.

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 already support addition natively.

multiplication

public void multiplication()
                    throws IOException,
ClassNotFoundException,
IllegalArgumentException,
HomomorphicException

Performs multiplication on blinded encrypted values from alice.

Specified by:

multiplication in interface bob_interface

Overrides:

multiplication in class bob

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.

division

public void division(long divisor)
              throws ClassNotFoundException,
IOException,
IllegalArgumentException,
HomomorphicException

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

Specified by:

division in interface bob_interface

Overrides:

division in class bob

Parameters:

divisor - the divisor to divide the encrypted value by.

Throws:

ClassNotFoundException - if a class cannot be found during deserialization.

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

IllegalArgumentException - if invalid arguments are provided.

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

sort

public void sort()
          throws IOException,
ClassNotFoundException,
IllegalArgumentException,
HomomorphicException

See the papers "Improving the DGK comparison protocol" and Correction to ”Improving the DGK comparison protocol” by Thjis Veugen, You can find these in the papers directory! Sorts a list of encrypted numbers using Protocol 4 (see the Veugen papers). This method is used when Alice wants to sort encrypted numbers securely.

Specified by:

sort in interface bob_interface

Overrides:

sort in class bob

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 an error occurs during the sorting process.

Protocol2

public boolean Protocol2()
                  throws IOException,
ClassNotFoundException,
IllegalArgumentException,
HomomorphicException

See the papers "Improving the DGK comparison protocol" and Correction to ”Improving the DGK comparison protocol” by Thjis Veugen, You can find these in the papers directory! Sorts a list of encrypted numbers using Protocol 4 (see the Veugen papers). This method is used when Alice wants to sort encrypted numbers securely.

Specified by:

Protocol2 in interface bob_interface

Overrides:

Protocol2 in class bob_veugen

Returns:

true if the comparison result indicates x >= y, false otherwise.

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.