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corda / bn-extension

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Business networks and memberships

The Corda platform extension for creating and managing business networks allows a node operator to define and create a logical network based on a set of common CorDapps as well as a shared business context. Corda nodes outside of a business network are not aware of its members. The network can be split into subgroups or membership lists which allows for further privacy (members of a group only know about those in their group).

In a business network, there is at least one authorised member. This member has sufficient permissions to execute management operations over the network and its members.

Installation

Add the business-networks-contracts dependency in your "contracts" (and states) cordapp module:

dependencies {
    //...
    cordapp("net.corda.bn:business-networks-contracts:$corda_bn_extension_version")
    //...
}

... and the business-networks-workflows dependency in your "workflows" cordapp module:

dependencies {
    //...
    cordapp("net.corda.bn:business-networks-workflows:$corda_bn_extension_version")
    //...
}

Remember to add both dependencies in your Cordform (i.e. deployNodes) task.

Creating and managing a business network

BNE provides a set of workflows that allows a user to start a business network, on-board members and assign them to membership lists or groups. The flows can also be used to update the information in the memberships (update business network identity, modify member roles) and manage them (suspend or revoke members).

Create a business network

Either from the node shell or from an RPC client, run CreateBusinessNetworkFlow. This will self issue a membership with an exhaustive permissions set that will allow the calling node to manage future operations for the newly created network.

Flow arguments:

Example:

val myIdentity: BNIdentity = createBusinessNetworkIdentity() // mock method that creates an instance of a class implementing [BNIdentity]
val groupId = UniqueIdentifier()
val notary = serviceHub.networkMapCache.notaryIdentities.first()

subFlow(CreateBusinessNetworkFlow("MyBusinessNetwork", myIdentity, groupId, "Group 1", notary))

On-board a new member

Joining a business network is a 2 step process. First, the Corda node wishing to join must run the RequestMembershipFlow either from the node shell or any other RPC client. As a result of a successful run, a membership is created with a PENDING status and all authorised members will be notified of any future operations involving it. Until activated by an authorised party (a business network operator for instance) the newly generated membership can neither be used nor grant the requesting node any permissions in the business network.

RequestMembershipFlow arguments:

Example:

val myIdentity: BNIdentity = createBusinessNetworkIdentity() // create an instance of a class implementing [BNIdentity]
val networkId = "MyBusinessNetwork"
val bno: Party = ... // get the [Party] object of the Corda node acting as a BNO for the business network represented by [networkId]
val notary = serviceHub.networkMapCache.notaryIdentities.first())

subFlow(RequestMembershipFlow(bno, networkId, myIdentity, notary))

To finalise the on-boarding process, an authorised party needs to run the ActivateMembershipFlow. This will update the targeted membership status from PENDING to ACTIVE after signatures are collected from all authorised parties in the network. After activation, the activating party needs to follow-up with a group assignment by running the ModifyGroupFlow.

ActivateMembershipFlow arguments:

Example:

val bnService = serviceHub.cordaService(BNService::class.java)
val networkId = "MyBusinessNetwork"
val newMemberPartyObject = ... // get the [Party] object of the member whose membership is being activated
val membershipId = bnService.getMembership("MyBusinessNetwork", newMemberPartyObject)
val groupName = "Group 1"
val groupId = ... // identifier of the group which the member will be assigned to
val notary = serviceHub.networkMapCache.notaryIdentities.first()

subFlow(ActivateMembershipFlow(membershipId, notary))

// add newly activated member to a membership list
val newParticipantsList = bnService.getBusinessNetworkGroup(groupId).state.data.participants.map {
    BNService.getMembership(networkId, it)!!.state.data.linearId
} + membershipId

subFlow(ModifyGroupFlow(groupId, groupName, newParticipantsList, notary))

Onboarding new member can also be done without prior membership request. Authorised party needs to run OnboardMembershipFlow to directly issue a new membership with ACTIVE status. After onboarding, authorised member also needs to follow-up with a group assignment by running the ModifyGroupFlow.

OnboardMembershipFlow arguments:

Example:

val bnService = serviceHub.cordaService(BNService::class.java)
val networkId = "MyBusinessNetwork"
val onboardedParty = ... // get the [Party] object of the Corda node acting as an onboarded member
val businessIdentity: BNIdentity = createBusinessNetworkIdentity() // create an instance of a class implementing [BNIdentity]
val notary = serviceHub.networkMapCache.notaryIdentities.first()
val groupId = ... // identifier of the group which the member will be assigned to
val groupName = "Group 1"

subFlow(OnboardMembershipFlow(networkId, onboardedParty, businessIdentity, notary))

// add newly activated member to a membership list
val membershipId = bnService.getMembership(networkId, onboardedParty)!!.state.data.linearId
val newParticipantsList = bnService.getBusinessNetworkGroup(groupId).state.data.participants.map {
    BNService.getMembership(networkId, it)!!.state.data.linearId
} + membershipId

subFlow(ModifyGroupFlow(groupId, groupName, newParticipantsList, notary))

Amend a membership

There are several ways in which a member's information can be updated, not including network operations such as membership suspension or revocation. These attributes which can be amended are: business network identity, membership list or group, and roles.

To update a member's business identity attribute, one of the authorised network parties needs to run the ModifyBusinessIdentityFlow which then requires all network members with sufficient permissions to approve the proposed change.

ModifyBusinessIdentityFlow arguments:

Example:

val bnService = serviceHub.cordaService(BNService::class.java)
val networkId = "MyBusinessNetwork"
val partyToBeUpdated = ... // get the [Party] object of the member being updated
val membership = bnService.getMembership(networkId, partyToBeUpdated)
val updatedIdentity: BNIdentity = updateBusinessIdentity(membership.state.data.identity) // mock method that updates the business identity in some meaningful way
val notary = serviceHub.networkMapCache.notaryIdentities.first())

subFlow(ModifyBusinessIdentityFlow(membership.state.data.linearId, updatedIdentity, notary))

Updating a member's roles and permissions in the business network is done in a similar fashion by using the ModifyRolesFlow. Depending on the proposed changes, the updated member may become an authorised member. If that happens, an important thing to note is that this enhancement will have to be preceded by an execution of the ModifyGroupsFlow to add the member to all membership lists it will have administrative powers over.

ModifyRolesFlow arguments:

Example:

val roles = setOf(BNORole()) // assign full permissions to member
val bnService = serviceHub.cordaService(BNService::class.java)
val networkId = "MyBusinessNetwork"
val partyToBeUpdated = ... // get the [Party] object of the member being updated
val membershipId = bnService.getMembership(networkId, partyToBeUpdated).state.data.linearId
val notary = serviceHub.networkMapCache.notaryIdentities.first())

subFlow(ModifyRolesFlow(membershipId, roles, notary))

To manage the membership lists or groups, one of the authorised members of the network can use CreateGroupFlow, DeleteGroupFlow and ModifyGroupFlow.

CreateGroupFlow arguments:

Example:

val notary = serviceHub.networkMapCache.notaryIdentities.first())
val myNetworkId = "MyBusinessNetwork"
val myGroupId = UniqueIdentifier()
val groupName = "Group 1"

subFlow(CreateGroupFlow(myNetworkId, myGroupId, groupName, emptySet(), notary))

DeleteGroupFlow arguments:

The ModifyGroupFlow can update the name of a group and/or its list of members. At least one of the name or participants arguments must be provided.

ModifyGroupFlow arguments:

Example:

val bnService = serviceHub.cordaService(BNService::class.java)
val bnGroupId = ... // get the identifier of the group being updated
val bnGroupName = bnService.getBusinessNetworkGroup(bnGroupId).state.data.name
val participantsList = bnService.getBusinessNetworkGroup(bnGroupId).state.data.participants
val newParticipantsList = removeMember(someMember, participantsList) // mock method that removes a member from the group
val notary = serviceHub.networkMapCache.notaryIdentities.first())

subFlow(ModifyGroupFlow(bnGroupId, bnGroupName, newParticipantsList, notary))

Suspend or revoke a membership

Temporarily suspending a member or completely removing it from the business network is done using SuspendMembershipFlow and RevokeMembershipFlow. They both use the same exactly arguments:

Suspending a member will result in a membership status change to SUSPENDED and still allow said member to be in the business network. Revocation means that the membership is marked as historic/spent and and a new one will have to be requested and activated in order for the member to re-join the network.

Example:

val notary = serviceHub.networkMapCache.notaryIdentities.first())
val memberToBeSuspended = ... // get the linear ID of the membership state associated with the Party which is being suspended from the network
val memberToBeRevoked = ... // get the linear ID of the membership state associated with the Party which is being removed from the network

// Revocation
subFlow(RevokeMembershipFlow(memberToBeRevoked, notary))

// Suspension
subFlow(SuspendMembershipFlow(memberToBeSuspended, notary))

Request membership attribute changes

Using the RequestMembershipAttributeChangeFlow flow a member can create requests in order to change its attributes (business identity and roles). Note that when you request for new roles the changes will overwrite your existing roles. This flow will create a ChangeRequestState with PENDING status.

After the request creation an authorised member is able to decline the changes with using DeclineMembershipAttributeChangeFlow or accept using ApproveMembershipAttributeChangeFlow. If you decline the request the existingChangeRequestState will have DECLINED status. If you accept the request the existingChangeRequestState will have ACCEPTED status. There is also an option with DeleteMembershipAttributeChangeRequestFlow which marks these request as consumed to avoid stockpiling them in the database.

RequestMembershipAttributeChangeFlow arguments:

Example:

val authorisedParty: Party = ... // get the [Party] object of the authorised Corda node
val networkId = "MyBusinessNetwork"
val updatedIdentity: BNIdentity = ... // the new business identity you want to associate the member with, if you don't want to modify your existing business identity, then simply skip this step
val updatedRoles: Set<BNRole> = ... // the new roles you want to associate the member with, if you don't want to modify your existing roles, then simply skip this step
val notary = serviceHub.networkMapCache.notaryIdentities.first()

// Request creation
subFlow(RequestMembershipAttributeChangeFlow(authorisedParty, networkId, updatedIdentity, updatedRoles, notary))

ApproveMembershipAttributeChangeFlow arguments:

Example:

val requestId = ... // get the linear ID of the change request state associated with the Party which is requesting for attribute changes
val notary = serviceHub.networkMapCache.notaryIdentities.first()

// Approves request
subFlow(ApproveMembershipAttributeChangeFlow(requestId, notary))

DeclineMembershipAttributeChangeFlow arguments:

Example:

val requestId = ... // get the linear ID of the change request state associated with the Party which is requesting for attribute changes
val notary = serviceHub.networkMapCache.notaryIdentities.first()

// Declines request
subFlow(DeclineMembershipAttributeChangeFlow(requestId, notary))

DeleteMembershipAttributeChangeRequestFlow arguments:

Example:

val requestId = ... // get the linear ID of the change request state associated with the Party which is requesting for attribute changes
val notary = serviceHub.networkMapCache.notaryIdentities.first()

// Marks request as CONSUMED
subFlow(DeleteMembershipAttributeChangeRequestFlow(requestId, notary))

Composite Flows

We enhance existing Business Network management flow suite to make Business Network Operator's operations easier and more practical than before by introduction of Composite Flows. These are flows that call primitive Business Network management flows (ones under net.corda.bn.flows package). All of them are contained inside net.corda.bn.flows.composite package.

There are 2 flows released:

BatchActivateMembershipFlow arguments:

Example:

val (membershipId1, membershipId2) = ... // fetch pending memberships using [BNService]
val groupForMember1 = ... // get ID of the group where member1 will be added after activation
val memberships = setOf(
    ActivationInfo(membershipId = membershipId1, groupId = groupForMember1),
    ActivationInfo(membershipId = membershipId2, groupId = null)
)
val defaultGroupId = ... // get ID of the group where activated members will be added by default
val notary = serviceHub.networkMapCache.notaryIdentities.first()

subFlow(BatchActivateMembershipFlow(memberships, defaultGroupId, notary))

BatchOnboardMembershipFlow arguments:

Example:

val networkId = "MyBusinessNetwork"
val (party1, party2) = ... // get parties to be onboarded to the Business Network
val groupForParty1 = ... // get ID of the group where party1 will be added after onboarding
val businessIdentity1 = createBusinessNetworkIdentity() // mock method that creates an instance of a class implementing [BNIdentity]
val onboardedParties = setOf(
    OnboardingInfo(party = party1, businessIdentity = businessIdentity1, groupId = groupForParty1),
    OnboardingInfo(party = party2, businessIdentity = null, groupId = null)
)
val defaultGroupId = ... // get ID of the group where activated members will be added by default
val notary = serviceHub.networkMapCache.notaryIdentities.first()

subFlow(BatchOnboardMembershipFlow(networkId, onboardedParties, defaultGroupId, notary))

Access control report

The Business Network Operator (BNO) is able to ask for the access control report by calling BNOAccessControlReportFlow and receives the following information in the form of an AccessControlReport. Here are the attributes of the report file:

BNOAccessControlReportFlow arguments:

The path and fileName are optional arguments which means that they will have a default value if you don't define them. In this case the files will be written to the user.dir under the name of bno-access-control-report.

Example:

val networkId = "MyBusinessNetwork"
val path = ... // the absolute path where the report file should be placed
val fileName = ... // the name of the report file

subFlow(BNOAccessControlReportFlow(networkId, path, fileName))

Re-issue states affected by the change to a member's Corda Identity

It may happen that a member in the network needs to re-issue the certificate to which its Corda Identity binds. In that case, all membership and group states which are impacted should be re-issued with the new Corda Identity. This can be done using the UpdateCordaIdentityFlow. Please note that this flow requires the legal identity (CordaX500Name) to be the same. Furthermore, the flow can only be run from a member with sufficient permissions(can modify groups).

If several members of the network have their certificates rotated, it's important to start the identity update process with the authorised members as they are required to sign all other identity update transactions.

UpdateCordaIdentityFlow arguments:

Example:

val notary = serviceHub.networkMapCache.notaryIdentities.first())
val updatedMember = ... // get the linear ID of the membership state associated with the Party which was updated

subflow(UpdateCordaIdentityFlow(updatedMember, notary))