ch.epfl.dedis.lib.crypto

Class Mask

java.lang.Object

ch.epfl.dedis.lib.crypto.Mask

public class Mask
extends Object

Mask is a bitmask for a set of points.

Constructor Summary

Constructors

Constructor and Description
Mask(List<Point> publics, byte[] mask) Create a read-only mask from a set of public keys and the given bitmask.

Method Summary

Modifier and Type	Method and Description
int	countEnabled() Count the number of enabled public keys in the participation mask.
int	countTotal() Count the total number of public keys in this mask.
Point	getAggregate() Gets the aggregate public key according to the mask.
List<Point>	getPublics() Get the list of public keys involved in the mask
boolean	indexEnabled(int i) Checks whether the given index is enabled in the mask or not.
boolean	keyEnabled(Point p) Checks whether the index, corresponding to the given key, is enabled in the mask or not.
int	len() Gets the length of the mask in bytes.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Mask

public Mask(List<Point> publics,
            byte[] mask)
     throws CothorityCryptoException

Create a read-only mask from a set of public keys and the given bitmask.

Parameters:

publics - is the set of public keys.

mask - is the bit mask, the number of bits must be greater than or equal to the number of public keys.

Throws:

CothorityCryptoException - is thrown when the list of public keys is empty.

Method Detail

len

public int len()

Gets the length of the mask in bytes.

getAggregate

public Point getAggregate()

Gets the aggregate public key according to the mask.

getPublics

public List<Point> getPublics()

Get the list of public keys involved in the mask

Returns:

The list of public keys

indexEnabled

public boolean indexEnabled(int i)
                     throws IndexOutOfBoundsException

Checks whether the given index is enabled in the mask or not.

Parameters:

i - is the index.

Throws:

IndexOutOfBoundsException - when i >= the number of public keys.

keyEnabled

public boolean keyEnabled(Point p)
                   throws CothorityCryptoException

Checks whether the index, corresponding to the given key, is enabled in the mask or not.

Parameters:

p - is the public key.

Throws:

CothorityCryptoException - if the key is not found.

countEnabled

public int countEnabled()

Count the number of enabled public keys in the participation mask.

countTotal

public int countTotal()

Count the total number of public keys in this mask.

toString

public String toString()

Overrides:

toString in class Object