ch.epfl.dedis.lib.omniledger.darc

Class Darc

java.lang.Object

ch.epfl.dedis.lib.omniledger.darc.Darc

public class Darc
extends Object

Darc stands for distributed access right control. It provides a powerful access control policy that supports logical expressions, delegation of rights, offline verification and so on. Please refer to https://github.com/dedis/cothority/omniledger/README.md#darc for more information.

Constructor Summary

Constructors

Constructor and Description
Darc(byte[] buf)
Darc(DarcProto.Darc proto)
Darc(List<Identity> owners, List<Identity> signers, byte[] desc) Convenience constructor
Darc(Map<String,byte[]> rules, byte[] desc) The Darc constructor.

Method Summary

Modifier and Type	Method and Description
Darc	copy()
Darc	copyEvolve()
DarcId	getBaseId() Gets the base-ID of the darc, i.e.
DarcId	getId() Calculate the getId of the darc by calculating the sha-256 of the invariant parts which excludes the delegation-signature.
DarcId	getPrevID()
long	getVersion()
void	increaseVersion() Updates the version of the darc and clears any eventual signatures from previous evolutions.
static Map<String,byte[]>	initRules(List<Identity> owners, List<Identity> signers) This is a convenience function that initialise a set of rules with the default actions "_evolve" and "_sign".
void	setBaseId(DarcId id)
void	setPrevId(Darc d)
void	setPrevId(DarcId id)
void	setRule(String action, byte[] expression) Sets a rule to be the action/expression pair.
DarcProto.Darc	toProto() Creates the protobuf representation of the darc.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Darc

public Darc(Map<String,byte[]> rules,
            byte[] desc)

The Darc constructor.

Parameters:

rules - The initial set of rules, consider using initRules to create them.

desc - The description.

Darc

public Darc(List<Identity> owners,
            List<Identity> signers,
            byte[] desc)

Convenience constructor

Parameters:

owners - a list of owners that are allowed to evolve the darc

signers - a list of signers on behalf of that darc

desc - free form description of the darc

Darc

public Darc(DarcProto.Darc proto)
     throws CothorityCryptoException

Throws:

CothorityCryptoException

Darc

public Darc(byte[] buf)
     throws com.google.protobuf.InvalidProtocolBufferException,
            CothorityCryptoException

Throws:

com.google.protobuf.InvalidProtocolBufferException

CothorityCryptoException

Method Detail

setRule

public void setRule(String action,
                    byte[] expression)

Sets a rule to be the action/expression pair. This will overwrite an existing rule or create a new one.

Parameters:

action -

expression -

increaseVersion

public void increaseVersion()
                     throws CothorityCryptoException

Updates the version of the darc and clears any eventual signatures from previous evolutions.

Throws:

CothorityCryptoException

toProto

public DarcProto.Darc toProto()

Creates the protobuf representation of the darc.

Returns:

The protobuf representation.

getId

public DarcId getId()
             throws CothorityCryptoException

Calculate the getId of the darc by calculating the sha-256 of the invariant parts which excludes the delegation-signature.

Returns:

sha256

Throws:

CothorityCryptoException

setPrevId

public void setPrevId(DarcId id)

Parameters:

id - the id of the previous darc.

setBaseId

public void setBaseId(DarcId id)

Parameters:

id - the base-id to set

setPrevId

public void setPrevId(Darc d)
               throws CothorityCryptoException

Parameters:

d - the previous darc

Throws:

CothorityCryptoException

getBaseId

public DarcId getBaseId()
                 throws CothorityCryptoException

Gets the base-ID of the darc, i.e. the ID before any evolution.

Returns:

base-ID

Throws:

CothorityCryptoException

getPrevID

public DarcId getPrevID()

getVersion

public long getVersion()

Returns:

the current version.

copy

public Darc copy()
          throws CothorityCryptoException

Returns:

a copy of the darc with the same version number.

Throws:

CothorityCryptoException

copyEvolve

public Darc copyEvolve()
                throws CothorityCryptoException

Returns:

a copy of the darc with the next version number and prevId and baseId set up.

Throws:

CothorityCryptoException

toString

public String toString()

Overrides:

toString in class Object

initRules

public static Map<String,byte[]> initRules(List<Identity> owners,
                                           List<Identity> signers)

This is a convenience function that initialise a set of rules with the default actions "_evolve" and "_sign". Signers are joined with logical-Or, owners are joined with logical-AND. If other expressions are needed, please set the rules manually.

Parameters:

owners - A list of owners.

signers - A list of signers.

Returns:

The action-expression mapping, also known as the rule.