org.cryptimeleon.craco.secretsharing.accessstructure

Class AccessStructure

java.lang.Object

org.cryptimeleon.craco.secretsharing.accessstructure.AccessStructure

All Implemented Interfaces:

LinearSecretSharing<PolicyFact>

Direct Known Subclasses:

MonotoneSpanProgram

public abstract class AccessStructure
extends java.lang.Object
implements LinearSecretSharing<PolicyFact>

This is an abstract implementation of LinearSecretSharing for schemes that are based on special threshold trees, where leaf nodes correspond to shares. An additional map associates a share receiver to each number/leaf.

See Also:

LinearSecretSharing

Field Summary

Fields

Modifier and Type	Field and Description
protected org.cryptimeleon.math.structures.rings.zn.Zp	field The field over which the shares of the secret and the constants of the solving vector will be calculated.
protected java.util.HashMap<java.lang.Integer,PolicyFact>	shareReceivers Maps share indices to the share receivers they belong to.
protected TreeNode	thresholdTree The root node of the threshold tree underlying this access structure.

Constructor Summary

Constructors

Constructor and Description
AccessStructure(Policy policy, org.cryptimeleon.math.structures.rings.zn.Zp field) Constructs the access structure from policy to share over field.

Method Summary

Modifier and Type	Method and Description
org.cryptimeleon.math.structures.rings.zn.Zp	getSharedRing() Returns the ring over which the secret is being shared.
java.util.Map<java.lang.Integer,PolicyFact>	getShareReceiverMap() Returns the map that assigns each index i of a share \(s_i\) to its share receiver.
boolean	isQualified(java.util.Set<? extends PolicyFact> setOfShareReceivers) Checks whether or not the given set of share receivers will be able to recreate the secret by pooling their shares \(\{s_i \; | \; \text{getShareReceiver}(i) \in \text{setOfShareReceivers}\}\).
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.craco.secretsharing.LinearSecretSharing

checkShareConsistency, completeShares, getShareReceiver, getShares, getSharesOfReceiver, getSharesOfReceivers, getSolvingVector, isQualified, reconstruct

Field Detail

thresholdTree

protected TreeNode thresholdTree

The root node of the threshold tree underlying this access structure.

field

protected org.cryptimeleon.math.structures.rings.zn.Zp field

The field over which the shares of the secret and the constants of the solving vector will be calculated.

shareReceivers

protected java.util.HashMap<java.lang.Integer,PolicyFact> shareReceivers

Maps share indices to the share receivers they belong to.

Constructor Detail

AccessStructure

public AccessStructure(Policy policy,
                       org.cryptimeleon.math.structures.rings.zn.Zp field)

Constructs the access structure from policy to share over field.

Method Detail

isQualified

public boolean isQualified(java.util.Set<? extends PolicyFact> setOfShareReceivers)
                    throws WrongAccessStructureException

Description copied from interface: LinearSecretSharing

Checks whether or not the given set of share receivers will be able to recreate the secret by pooling their shares \(\{s_i \; | \; \text{getShareReceiver}(i) \in \text{setOfShareReceivers}\}\).

Specified by:

isQualified in interface LinearSecretSharing<PolicyFact>

Parameters:

setOfShareReceivers - the set of share receivers to check

Returns:

true if the shares of the given share receivers suffice to recreate a shared secret

Throws:

WrongAccessStructureException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getShareReceiverMap

public java.util.Map<java.lang.Integer,PolicyFact> getShareReceiverMap()

Description copied from interface: LinearSecretSharing

Returns the map that assigns each index i of a share \(s_i\) to its share receiver.

Specified by:

getShareReceiverMap in interface LinearSecretSharing<PolicyFact>

getSharedRing

public org.cryptimeleon.math.structures.rings.zn.Zp getSharedRing()

Description copied from interface: LinearSecretSharing

Returns the ring over which the secret is being shared.

Specified by:

getSharedRing in interface LinearSecretSharing<PolicyFact>