org.cryptimeleon.math.structures.groups.cartesian

Class ProductGroup

java.lang.Object

org.cryptimeleon.math.structures.groups.cartesian.ProductGroup

All Implemented Interfaces:

RepresentationRestorer, Representable, StandaloneRepresentable, Group, Structure

public class ProductGroup
extends java.lang.Object
implements Group

Field Summary

Fields

Modifier and Type	Field and Description
protected Group[]	groups

Constructor Summary

Constructors

Constructor and Description
ProductGroup(Group... groups)
ProductGroup(Representation repr)

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object other)
GroupElement	getNeutralElement() Returns the neutral element for this group
Representation	getRepresentation() The representation of this object.
GroupElement	getUniformlyRandomElement() Returns an element of this structure that is drawn uniformly at random using a cryptographically strong RNG.
java.util.Optional<java.lang.Integer>	getUniqueByteLength() Returns the number of bytes returned by this structure's UniqueByteRepresentable.getUniqueByteRepresentation(), or an empty Optional if this structure's elements do not guarantee a fixed length.
int	hashCode()
boolean	isCommutative() Returns true if this group is known to be commutative.
GroupElement	restoreElement(Representation repr) Creates an element of this structure from its representation.
java.math.BigInteger	size() Returns the number of elements in this structure (the size).
static ProductGroupElement	valueOf(GroupElement... elems)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.math.structures.groups.Group

expr, getGenerator, getUniformlyRandomElements, getUniformlyRandomExponent, getUniformlyRandomExponents, getUniformlyRandomNonNeutral, getUniformlyRandomNonNeutrals, getUniformlyRandomNonzeroExponent, getUniformlyRandomNonzeroExponents, getUniformlyRandomUnitExponent, getUniformlyRandomUnitExponents, getZn, restoreFromRepresentation, restoreVector

Methods inherited from interface org.cryptimeleon.math.structures.Structure

hasPrimeSize

Field Detail

groups

protected Group[] groups

Constructor Detail

ProductGroup

public ProductGroup(Group... groups)

ProductGroup

public ProductGroup(Representation repr)

Method Detail

getNeutralElement

public GroupElement getNeutralElement()

Description copied from interface: Group

Returns the neutral element for this group

Specified by:

getNeutralElement in interface Group

size

public java.math.BigInteger size()
                          throws java.lang.UnsupportedOperationException

Description copied from interface: Structure

Returns the number of elements in this structure (the size).

Specified by:

size in interface Structure

Returns:

the number of elements contained in this structure or null if infinite

Throws:

java.lang.UnsupportedOperationException - if the number of elements is unknown or too expensive to compute

getUniformlyRandomElement

public GroupElement getUniformlyRandomElement()
                                       throws java.lang.UnsupportedOperationException

Description copied from interface: Structure

Returns an element of this structure that is drawn uniformly at random using a cryptographically strong RNG.

Specified by:

getUniformlyRandomElement in interface Group

Specified by:

getUniformlyRandomElement in interface Structure

Throws:

java.lang.UnsupportedOperationException - if the operation is not supported

restoreElement

public GroupElement restoreElement(Representation repr)

Description copied from interface: Structure

Creates an element of this structure from its representation.

Specified by:

restoreElement in interface Group

Specified by:

restoreElement in interface Structure

Parameters:

repr - the Representation returned by Representable.getRepresentation()

Returns:

the decoded element corresponding to the representation

getUniqueByteLength

public java.util.Optional<java.lang.Integer> getUniqueByteLength()

Description copied from interface: Structure

Returns the number of bytes returned by this structure's UniqueByteRepresentable.getUniqueByteRepresentation(), or an empty Optional if this structure's elements do not guarantee a fixed length.

For example, elements of Zp will always be represented by ceil(ceil(log(p))/8) bytes, hence getUniqueByteLength() would return ceil(ceil(log(p))/8).

A polynomial ring would return an empty Optional since a polynomial's unique byte representation length depends on its degree.

Specified by:

getUniqueByteLength in interface Structure

Returns:

the guaranteed fixed length of getUniqueByteRepresentation(), or an empty Optional, if no guarantee

isCommutative

public boolean isCommutative()

Description copied from interface: Group

Returns true if this group is known to be commutative.

Specified by:

isCommutative in interface Group

getRepresentation

public Representation getRepresentation()

Description copied from interface: Representable

The representation of this object. Used for serialization. A convenient way to implement this is using @link ReprUtil

Specified by:

getRepresentation in interface Representable

Returns:

a Representation or null if an equal object can be recreated without any information.

See Also:

Representation

valueOf

public static ProductGroupElement valueOf(GroupElement... elems)

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object