Blacklist CorDapp

This CorDapp allows nodes to reach agreement over arbitrary strings of text, but only with parties that are not included in the blacklist uploaded to the nodes.

The blacklist takes the form of a jar including a single file, blacklist.txt. blacklist.txt lists the following parties as being banned from entering into agreements:

Crossland Savings
TCF National Bank Wisconsin
George State Bank
The James Polk Stone Community Bank
Tifton Banking Company

The blacklist jar is uploaded as an attachment when building a transaction, and used in the AgreementContract to check that the parties to the AgreementState are not blacklisted.

Pre-requisites:

See https://docs.corda.net/getting-set-up.html.

Usage

Running the nodes:

See https://docs.corda.net/tutorial-cordapp.html#running-the-example-cordapp.

Uploading the blacklist:

Before attempting to reach any agreements, you must upload the blacklist as an attachment to each node that you want to be able to initiate an agreement. The blacklist can be uploaded via RPC or HTTP.

Via RPC

Run the following command from within the attachments folder:

Unix/Mac OSX: ./gradlew uploadBlacklist
Windows: gradlew uploadBlacklist

You should see three messages of the form Blacklist uploaded to node via localhost:100XX.

Via HTTP

Visit the web API of the node for which you want to upload the attachment. Each node exposes their web API on a different address:

Monogram Bank: localhost:10007/
Hiseville Deposit Bank: localhost:10010/
George State Bank: localhost:10013/

Click Choose file to select the .jar containing the blacklist (under src/main/resources/blacklist.jar) and click Upload blacklist to upload it to the node.

Interacting with the nodes:

You can now interact with this CorDapp using its web API. Each node exposes this web API on a different address:

Monogram Bank: localhost:10007/web/option
Hiseville Deposit Bank: localhost:10010/web/option
George State Bank: localhost:10013/web/option

Note that George State Bank is a blacklisted entity, and the AgreementContract will prevent it from entering into agreements with other nodes.

The web API for each node exposes two endpoints:

/api/a/propose-agreement?counterparty=X&agreement=Y, which causes the node to reach agreement Y with counterparty X
/api/a/agreements, which lists the node's existing AgreementStates

For example, Monogram Bank and Hiseville Deposit Bank may enter into an agreement by visiting the following URL:

http://localhost:10007/api/a/propose-agreement?counterparty=Hiseville Deposit Bank&agreement=A and B agree Y

You should see the following message:

Agreement reached.

If you now visit http://localhost:10007/api/a/agreements, you should see the agreement stored on the node:

[ {
  "partyA" : "C=GB,L=London,O=Monogram Bank",
  "partyB" : "C=BR,L=Sao Paulo,O=Hiseville Deposit Bank",
  "txt" : "A and B agree Y",
  "participants" : [ "C=GB,L=London,O=Monogram Bank", "C=BR,L=Sao Paulo,O=Hiseville Deposit Bank" ]
} ]

However, if you visit the following URL to attempt to enter into an agreement with George State Bank:

http://localhost:10007/api/a/propose-agreement?counterparty=George State Bank&agreement=A and B agree Y

You will see the following message:

Contract verification failed: Failed requirement: The agreement involved blacklisted parties: [George State Bank]

And no agreement will be stored!

To-Do

Currently, the blacklist jar's hash is hardcoded in the contract. An improvement would be to support any jar signed by a specific trusted node

josecoll/blacklist