Package edu.fiu.adwise.homomorphic_encryption.dgk

Class DGKPublicKey

java.lang.Object

edu.fiu.adwise.homomorphic_encryption.dgk.DGKPublicKey

All Implemented Interfaces:

DGK_Key, CipherConstants, Serializable, Runnable, Key, PublicKey

public final class DGKPublicKey
extends Object
implements Serializable, DGK_Key, PublicKey, Runnable, CipherConstants

Represents the public key for the DGK (Damgård-Geisler-Krøigaard) cryptosystem. This class implements the Serializable, DGK_Key, PublicKey, Runnable, and CipherConstants interfaces. It provides methods for key generation, serialization, and lookup table generation for encryption operations.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
BigInteger	ONE	The encrypted representation of the value 1.
BigInteger	ZERO	The encrypted representation of the value 0.

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
DGKPublicKey(BigInteger n, BigInteger g, BigInteger h, BigInteger u, int l, int t, int k)	Constructs a DGKPublicKey with all required parameters.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)	Compares this DGKPublicKey with another object for equality.
String	getAlgorithm()
byte[]	getEncoded()
String	getFormat()
int	getL()	Retrieves the bit length \( l \) of the DGK key.
BigInteger	getN()	Retrieves the modulus \( n \) associated with the DGK key.
int	getT()
long	getu()
BigInteger	getU()	Retrieves the value of \( u \), a parameter associated with the DGK key.
static DGKPublicKey	readKey(String dgk_public_key)	Deserializes a DGKPublicKey from a file.
void	run()	Generates the lookup tables for g and h.
String	toString()
void	writeKey(String dgk_public_key_file)	Serializes the public key to a file.
BigInteger	ZERO()

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

ONE

public BigInteger ONE

The encrypted representation of the value 1.

ZERO

public BigInteger ZERO

The encrypted representation of the value 0.

Constructor Details

DGKPublicKey

public DGKPublicKey(BigInteger n,
 BigInteger g,
 BigInteger h,
 BigInteger u,
 int l,
 int t,
 int k)

Constructs a DGKPublicKey with all required parameters.

Parameters:

n - The modulus.

g - The generator.

h - The secondary generator.

u - The order of the subgroup.

l - The bit length of plaintext.

t - The security parameter.

k - The key size.

Method Details

writeKey

public void writeKey(String dgk_public_key_file)
              throws IOException

Serializes the public key to a file.

Parameters:

dgk_public_key_file - The file path to save the public key.

Throws:

IOException - If an I/O error occurs.

readKey

public static DGKPublicKey readKey(String dgk_public_key)
                            throws IOException,
ClassNotFoundException

Deserializes a DGKPublicKey from a file.

Parameters:

dgk_public_key - The file path to read the public key from.

Returns:

The deserialized DGKPublicKey.

Throws:

IOException - If an I/O error occurs.

ClassNotFoundException - If the class cannot be found.

ZERO

public BigInteger ZERO()
                throws HomomorphicException

Returns:

The encrypted representation of 0.

Throws:

HomomorphicException - - If an invalid input was found, this should be impossible in this case

getAlgorithm

public String getAlgorithm()

Specified by:

getAlgorithm in interface Key

Returns:

The algorithm name ("DGK").

toString

public String toString()

Overrides:

toString in class Object

Returns:

A string representation of the DGK public key.

getFormat

public String getFormat()

Specified by:

getFormat in interface Key

Returns:

The format of the key ("X.509").

getEncoded

public byte[] getEncoded()

Specified by:

getEncoded in interface Key

Returns:

The encoded form of the key (currently null).

run

public void run()

Generates the lookup tables for g and h.

Specified by:

run in interface Runnable

getu

public long getu()

Returns:

The order of the subgroup as a long.

getU

public BigInteger getU()

Description copied from interface: DGK_Key

Retrieves the value of \( u \), a parameter associated with the DGK key.

Specified by:

getU in interface DGK_Key

Returns:

The order of the subgroup as a BigInteger.

getN

public BigInteger getN()

Description copied from interface: DGK_Key

Retrieves the modulus \( n \) associated with the DGK key.

Specified by:

getN in interface DGK_Key

Returns:

The modulus n.

getL

public int getL()

Description copied from interface: DGK_Key

Retrieves the bit length \( l \) of the DGK key.

Specified by:

getL in interface DGK_Key

Returns:

The bit length of plaintext.

getT

public int getT()

Returns:

The security parameter.

equals

public boolean equals(Object o)

Compares this DGKPublicKey with another object for equality.

Overrides:

equals in class Object

Parameters:

o - The object to compare with.

Returns:

True if the objects are equal, false otherwise.