ch.epfl.dedis.lib.darc

Class Darc

java.lang.Object

ch.epfl.dedis.lib.darc.Darc

public class Darc
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
List<Identity>	owners

Constructor Summary

Constructors

Constructor and Description
Darc() Overloaded function to create an empty darc.
Darc(DarcOCSProto.Darc proto) Returns a darc from a protobuf representation.
Darc(Identity owner, List<Identity> users, byte[] data) Initialize a darc by giving an owner that is allowed to evolve the darc and a list of users allowed to sign actions on behalf of that darc.
Darc(List<Identity> owners, List<Identity> users, byte[] data) Initialize a darc by giving an owner that is allowed to evolve the darc and a list of users allowed to sign actions on behalf of that darc.
Darc(Signer owner, List<Signer> users, byte[] data) Overloaded function for convenience.

Method Summary

Modifier and Type	Method and Description
void	addOwner(Darc darc) Adds an owner to the list of allowed signers.
void	addOwner(Identity identity) Adds a owner to the list of allowed signers.
void	addOwner(Signer signer) Adds a owner to the list of allowed signers.
void	addUser(Darc darc) Adds a user to the list of allowed signers.
void	addUser(Identity identity) Adds a user to the list of allowed signers.
void	addUser(Signer signer) Adds a user to the list of allowed signers.
Darc	copy() Creates a copy of the current darc and increases the version-number by 1.
boolean	equals(Darc d)
DarcId	getBaseId() Returns the id of the darc with version == 0.
byte[]	getData()
DarcId	getId() Calculate the getId of the darc by calculating the sha-256 of the invariant parts which excludes the delegation-signature.
List<Identity>	getOwners() Retrun copy of current owners of DARC
List<Identity>	getUsers() Return copy of current users of DARC (users/dacs who can execute this DARC)
int	getVersion() Returns the current version
void	incVersion() Increments the version of this Darc by 1.
void	removeOwner(Darc darc)
void	removeOwner(Identity identity)
void	removeOwner(Signer signer)
void	removeUser(Darc darc)
void	removeUser(Identity identity)
void	removeUser(Signer signer)
void	setEvolution(Darc previous, Signer previousOwner) To evolve a darc, the latest valid darc needs to sign the new darc.
void	setEvolutionOffline(Darc previous, SignaturePath path, Signer previousOwner) To evolve a darc, the latest valid darc needs to sign the new darc.
DarcOCSProto.Darc	toProto() Creates a protobuf representation of the darc.
String	toString()
boolean	verifyEvolution(Darc previous) Returns true if the current darc has correctly been evolved from the previous darc.

Methods inherited from class java.lang.Object

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

Field Detail

owners

public List<Identity> owners

Constructor Detail

Darc

public Darc(List<Identity> owners,
            List<Identity> users,
            byte[] data)
     throws CothorityCryptoException

Initialize a darc by giving an owner that is allowed to evolve the darc and a list of users allowed to sign actions on behalf of that darc. The data fieldElement can be used for any application-specific usage and will not be interpreted by darc or onchain-secrets.

Parameters:

owners - defines who will be allowed to evolve that darc

users - defines who can sign on behalf of that darc

Throws:

CothorityCryptoException

Darc

public Darc(Identity owner,
            List<Identity> users,
            byte[] data)
     throws CothorityException

Initialize a darc by giving an owner that is allowed to evolve the darc and a list of users allowed to sign actions on behalf of that darc. The data fieldElement can be used for any application-specific usage and will not be interpreted by darc or onchain-secrets.

Parameters:

owner - defines who will be allowed to evolve that darc

users - defines who can sign on behalf of that darc

Throws:

CothorityException

Darc

public Darc(Signer owner,
            List<Signer> users,
            byte[] data)
     throws CothorityCryptoException

Overloaded function for convenience. Directly creates the Identities from the signers.

Parameters:

owner -

users -

data -

Throws:

CothorityCryptoException

Darc

public Darc()

Overloaded function to create an empty darc.

Darc

public Darc(DarcOCSProto.Darc proto)
     throws CothorityCryptoException

Returns a darc from a protobuf representation.

Parameters:

proto -

Throws:

CothorityCryptoException

Method Detail

copy

public Darc copy()
          throws CothorityCryptoException

Creates a copy of the current darc and increases the version-number by 1. Once the new darc is configured, setEvolution has to be called last on the new darc.

Returns:

new darc

Throws:

CothorityCryptoException

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

setEvolution

public void setEvolution(Darc previous,
                         Signer previousOwner)
                  throws CothorityCryptoException

To evolve a darc, the latest valid darc needs to sign the new darc. Only if one of the previous owners signs off on the new darc will it be valid and accepted to sign on behalf of the old darc. The path can be nil unless if the previousOwner is an SignerEd25519 and found directly in the previous darc.

If a new darc is signed with this method, it will only be verifiable in a setting where the verifier has access to the previous darc. This is OK in the case of OCS, but might not be OK if you would want to verify it without having access to the previous darc.

The verification will have to be done on the OCS skipchain.

Parameters:

previous -

previousOwner -

Throws:

CothorityCryptoException

setEvolutionOffline

public void setEvolutionOffline(Darc previous,
                                SignaturePath path,
                                Signer previousOwner)
                         throws CothorityCryptoException

To evolve a darc, the latest valid darc needs to sign the new darc. Only if one of the previous owners signs off on the new darc will it be valid and accepted to sign on behalf of the old darc. The path can be nil unless if the previousOwner is an SignerEd25519 and found directly in the previous darc.

Parameters:

previous -

path -

previousOwner -

Throws:

CothorityCryptoException

getBaseId

public DarcId getBaseId()
                 throws CothorityCryptoException

Returns the id of the darc with version == 0. If it's the darc with version 0, then it will return its own getId.

Returns:

id of first darc

Throws:

CothorityCryptoException

verifyEvolution

public boolean verifyEvolution(Darc previous)
                        throws CothorityCryptoException

Returns true if the current darc has correctly been evolved from the previous darc.

Parameters:

previous -

Returns:

Throws:

CothorityCryptoException

toProto

public DarcOCSProto.Darc toProto()

Creates a protobuf representation of the darc.

Returns:

the protobuf representation of the darc.

addUser

public void addUser(Identity identity)

Adds a user to the list of allowed signers.

Parameters:

identity -

addUser

public void addUser(Darc darc)
             throws CothorityCryptoException

Adds a user to the list of allowed signers.

Parameters:

darc -

Throws:

CothorityCryptoException

addUser

public void addUser(Signer signer)
             throws CothorityCryptoException

Adds a user to the list of allowed signers.

Parameters:

signer -

Throws:

CothorityCryptoException

removeOwner

public void removeOwner(Identity identity)

removeOwner

public void removeOwner(Darc darc)
                 throws CothorityCryptoException

Throws:

CothorityCryptoException

removeOwner

public void removeOwner(Signer signer)
                 throws CothorityCryptoException

Throws:

CothorityCryptoException

removeUser

public void removeUser(Identity identity)

removeUser

public void removeUser(Darc darc)
                throws CothorityCryptoException

Throws:

CothorityCryptoException

removeUser

public void removeUser(Signer signer)
                throws CothorityCryptoException

Throws:

CothorityCryptoException

addOwner

public void addOwner(Identity identity)

Adds a owner to the list of allowed signers.

Parameters:

identity -

addOwner

public void addOwner(Darc darc)
              throws CothorityCryptoException

Adds an owner to the list of allowed signers.

Parameters:

darc -

Throws:

CothorityCryptoException

addOwner

public void addOwner(Signer signer)
              throws CothorityCryptoException

Adds a owner to the list of allowed signers.

Parameters:

signer -

Throws:

CothorityCryptoException

incVersion

public void incVersion()

Increments the version of this Darc by 1.

getVersion

public int getVersion()

Returns the current version

Returns:

getOwners

public List<Identity> getOwners()

Retrun copy of current owners of DARC

Returns:

list of owners

getUsers

public List<Identity> getUsers()

Return copy of current users of DARC (users/dacs who can execute this DARC)

Returns:

list of users

getData

public byte[] getData()

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Darc d)