org.apache.sysds.runtime.privacy.propagation

Class PrivacyPropagator

java.lang.Object

org.apache.sysds.runtime.privacy.propagation.PrivacyPropagator

public class PrivacyPropagator
extends Object

Class with static methods merging privacy constraints of operands in expressions to generate the privacy constraints of the output.

Constructor Summary

Constructors

Constructor and Description
PrivacyPropagator()

Method Summary

Modifier and Type	Method and Description
static PrivacyConstraint.PrivacyLevel	corePropagation(PrivacyConstraint.PrivacyLevel[] inputLevels, OperatorType operatorType) Returns the output privacy level based on the given input privacy levels and operator type.
static void	hopPropagation(Hop hop) Propagate privacy constraints from input hops to given hop.
static PrivacyConstraint	mergeBinary(PrivacyConstraint privacyConstraint1, PrivacyConstraint privacyConstraint2) Merges the input privacy constraints using the core propagation with NonAggregate operator type.
static PrivacyConstraint	parseAndReturnPrivacyConstraint(org.apache.wink.json4j.JSONObject mtd) Parses the privacy constraint of the given metadata object or returns null if no privacy constraint is set in the metadata.
static Data	parseAndSetPrivacyConstraint(Data cd, org.apache.wink.json4j.JSONObject mtd) Parses the privacy constraint of the given metadata object and sets the field of the given Data if the privacy constraint is not null.
static void	postProcessInstruction(Instruction inst, ExecutionContext ec) Propagate privacy constraints to output variables based on privacy constraint of CPOperand output in instruction which has been set during privacy propagation preprocessing.
static Instruction	preprocessInstruction(Instruction inst, ExecutionContext ec) Propagate privacy constraints from input to output CPOperands in case the privacy constraints of the input are activated.

Methods inherited from class java.lang.Object

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

Constructor Detail

PrivacyPropagator

public PrivacyPropagator()

Method Detail

parseAndSetPrivacyConstraint

public static Data parseAndSetPrivacyConstraint(Data cd,
                                                org.apache.wink.json4j.JSONObject mtd)
                                         throws org.apache.wink.json4j.JSONException

Parses the privacy constraint of the given metadata object and sets the field of the given Data if the privacy constraint is not null.

Parameters:

cd - data for which privacy constraint is set

mtd - metadata object

Returns:

data object with privacy constraint set

Throws:

org.apache.wink.json4j.JSONException - during parsing of metadata

parseAndReturnPrivacyConstraint

public static PrivacyConstraint parseAndReturnPrivacyConstraint(org.apache.wink.json4j.JSONObject mtd)
                                                         throws org.apache.wink.json4j.JSONException

Parses the privacy constraint of the given metadata object or returns null if no privacy constraint is set in the metadata.

Parameters:

mtd - metadata

Returns:

privacy constraint parsed from metadata object

Throws:

org.apache.wink.json4j.JSONException - during parsing of metadata

corePropagation

public static PrivacyConstraint.PrivacyLevel corePropagation(PrivacyConstraint.PrivacyLevel[] inputLevels,
                                                             OperatorType operatorType)

Returns the output privacy level based on the given input privacy levels and operator type. It represents the basic logic of privacy propagation: Unary input: Input | NonAggregate | Aggregate ----------------------------------- priv | priv | priv privAgg | privAgg | none none | none | none Binary input: Input | NonAggregate | Aggregate -------------------------------------------- priv-priv | priv | priv priv-privAgg | priv | priv priv-none | priv | priv privAgg-priv | priv | priv none-priv | priv | priv privAgg-privAgg | privAgg | none none-none | none | none privAgg-none | privAgg | none none-privAgg | privAgg | none

Parameters:

inputLevels - privacy levels of the input

operatorType - type of the operator which is either an aggregation (Aggregate) or not an aggregation (NonAggregate)

Returns:

output privacy level

mergeBinary

public static PrivacyConstraint mergeBinary(PrivacyConstraint privacyConstraint1,
                                            PrivacyConstraint privacyConstraint2)

Merges the input privacy constraints using the core propagation with NonAggregate operator type.

Parameters:

privacyConstraint1 - first privacy constraint

privacyConstraint2 - second privacy constraint

Returns:

merged privacy constraint

hopPropagation

public static void hopPropagation(Hop hop)

Propagate privacy constraints from input hops to given hop.

Parameters:

hop - which the privacy constraints are propagated to

postProcessInstruction

public static void postProcessInstruction(Instruction inst,
                                          ExecutionContext ec)

Propagate privacy constraints to output variables based on privacy constraint of CPOperand output in instruction which has been set during privacy propagation preprocessing.

Parameters:

inst - instruction for which privacy constraints are propagated

ec - execution context

preprocessInstruction

public static Instruction preprocessInstruction(Instruction inst,
                                                ExecutionContext ec)

Propagate privacy constraints from input to output CPOperands in case the privacy constraints of the input are activated.

Parameters:

inst - instruction for which the privacy constraints are propagated

ec - execution context

Returns:

instruction with propagated privacy constraints (usually the same instance as the input inst)