paillierp
Class PartialDecryption

java.lang.Object
  paillierp.PartialDecryption

All Implemented Interfaces:

java.io.Serializable

public class PartialDecryption
extends java.lang.Object
implements java.io.Serializable

A partial decryption in the Threshold Paillier encryption scheme with necessary data to proceed with the full decryption. To produce the full decryption of any ciphertext, at least w decryption servers must provide their partial decryptions. Furthermore, the source ID of each partial decryption is essential in combining the shares to produce a full and complete decryption of the original ciphertext. For this reason, a special datatype has been produced to hold only the partial decryption and the source ID.

Author:

James Garrity

See Also:

Serialized Form

Field Summary

private java.math.BigInteger	decryption The partial decryption
private int	id The ID number of the decryption server who decrypted this.
private static long	serialVersionUID This Serial ID

Constructor Summary

PartialDecryption(java.math.BigInteger decryption, int id)
Links the partial decryption decryption as coming from decryption server id.

PartialDecryption(byte[] b)
Translates a byte array, of which the first four bytes contain the id and the last number of bytes contain the two's complement binary representation of a BigInteger.

PartialDecryption(PaillierPrivateThresholdKey key, java.math.BigInteger ciphertext)
Computes the partial decryption of ciphertext using the private key key.

Method Summary

java.math.BigInteger	getDecryptedValue() Returns the partial decryption string
int	getID() Returns the ID of the secret key which produced this partial decryption
byte[]	toByteArray() Returns a byte array where the first four bytes signify the ID and the remaining signify the partial decryption.

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

This Serial ID

See Also:

Constant Field Values

decryption

private java.math.BigInteger decryption

The partial decryption

id

private int id

The ID number of the decryption server who decrypted this.

Constructor Detail

PartialDecryption

public PartialDecryption(java.math.BigInteger decryption,
                         int id)

Links the partial decryption decryption as coming from decryption server id.

Parameters:

decryption - a partial decryption

id - the id of the secret key who composed this partial decryption

PartialDecryption

public PartialDecryption(byte[] b)

Translates a byte array, of which the first four bytes contain the id and the last number of bytes contain the two's complement binary representation of a BigInteger.

Parameters:

b -

PartialDecryption

public PartialDecryption(PaillierPrivateThresholdKey key,
                         java.math.BigInteger ciphertext)

Computes the partial decryption of ciphertext using the private key key. This is essentially the value ciphertext^2Δs_i.

Parameters:

key - private key of decryption server i

ciphertext - original ciphertext

Method Detail

getDecryptedValue

public java.math.BigInteger getDecryptedValue()

Returns the partial decryption string

Returns:

the value c_i

getID

public int getID()

Returns the ID of the secret key which produced this partial decryption

Returns:

the secret key ID used

toByteArray

public byte[] toByteArray()

Returns a byte array where the first four bytes signify the ID and the remaining signify the partial decryption.

Returns:

byte array of the ID concatenated to byte array of the partial decryption.