Credit Protocol Documentation

Smart Contracts for Credit Protocol (CP)

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The Credit Protocol is a powerful blockchain solution to storing credits and debts on the blockchain. This doc will help walk you through interacting with and integrating the Credit Protocol into your UCAC (use case authority contract) which will be built atop the protocol. All docs here refer to the most updated version of the protocol at

Credit Protocol Smart Contracts

Ethereum Smart Contracts for the Debt Protocol dApp that faciliates debt tracking between any two parties.

Contract Addresses

  • Stake.sol 0xfA5B488799ae2514757Ba0a0a4DA7AB764e0f8d2
  • CreditProtocol.sol 0x9aa6596444eefaf28fda17be861adfac289c773f

How the Credit Protocol works


CreditProtocol.sol is mainly responsible for logging issuances of credit to the Ethereum blockchain. Credit can be issued under the following conditions:

  • Both parties in a debt relationship cryptographically sign the elements of a credit record

  • The UCAC contract which is referenced in the credit record acknowledges that the credit record is valid for its particular use case (see section UCAC contract for more information)

  • Users of the Credit Protocal have staked the UCAC contract with enough BCPT to handle the issuance of credit (see section Stake.sol for more information)

In addition to logging issuances of credit, CreditProtocol.sol maintains a mapping of the credit balances of all users. A unique user balance is maintained for every (UCAC, user) pair.

What is logged

event IssueCredit(bytes32 indexed ucac, address indexed creditor, address indexed debtor, uint256 amount);


Stake.sol is responsible for registering UCACs and rate-limiting their issuances of credit based on how many BCPT they’ve been staked with. The contract maintains a mapping of ucacIds to ucac information records; and is primary source of information on registerd UCACs.

UCAC information stored by Stake.sol

  • UCAC contract address
  • total number of tokens staked
  • “txLevel” which is a measure of how many credit transactions have been performed in the recent past. This is used by Stake.sol to rate limit transactions based on the number of tokens staked to a particular UCAC
  • timestamp of the last UCAC transaction
  • denomination of credit issued in the UCAC

UCAC Contract

A UCAC contract, the most basic of which can be seen here, is required to implement a single fuction with the following signature:

function allowTransaction(address creditor, address debtor, uint256 amount) public returns (bool)

allowTransaction is called by CreditProtocol.sol in its function issueCredit. By returning true, allowTransaction approves the issuance of credit; by returning false, allowTransaction can block the issuance of credit. Typically, a UCAC will use its power to appove transactions to make sure the transactions satisfy certain requirements. For example, a UCAC may want to block a transaction which involves any party who is too heavily in debt.


To run all testrpc tests, execute ./ To run only a specific test, execute ./ [path-to-test-file].