Flare: Transaction verification library

The repository contains a typescript library for verification of transactions on Flare and Songbird networks, as well as on Coston and Coston2 test networks, prior to their signing.

This library mitigates the main challenges encountered during transaction signing:

1. Unauthorized alterations to the transaction without user's knowledge before sending it to the wallet.
2. The absence of visibility into the transaction's content or parameters during the signing process (i.e., blind signing).
3. Uncertainty regarding the origin of the called contract, specifically whether it was published by Flare.

Usage

To install the library, run:

npm install @flarenetwork/flare-tx-verifier-lib

To verify a transaction (input), use asynchronous function verify that resolves to a TxVerification object or null:

import { verify } from "@flarenetwork/flare-tx-verifier-lib"

let verification = await verify(input)

The parameter input is a base64 or hex encoded unsigned C-chain or P-chain transaction. For convenience, it can also be a base64 or hex encoded GZIP compression of the transaction.

About verification process

The output of the function verify applied to the unsigned transaction will include the following parameters (depending on the type of transaction):

Output parameter	Description
network	Network name, e.g. Flare Mainnet. For non-flare networks, chainID is returned.
type	Possible transaction types are "transferC", "contractCallC", "exportC", "importC", "exportP", "importP", "addDelegatorP", "addValidatorP"
description	Description of the transaction type: "Funds transfer on C-chain", "Contract call on C-chain", "Export from C-chain", "Import to C-chain", "Export from P-chain", "Import to P-chain", "Stake on P-chain", "Add validator on P-chain".
recipients	Recipient(s) of funds or the address of the contract called.
values	Amount of funds transferred or staked stated in WEI.
fee	Transfer fee stated (if specified in transaction) stated in WEI.
contractName	When calling a C-chain contract, its name will be returned (if it exists).
contractMethod	When calling a C-chain contract, the method called will be returned (if it can be decoded).
contractMethodABI	When calling a C-chain contract, the ABI specification of the method called will be returned in JSON string format.
contractData	When calling a C-chain contract, the data field is returned (in hex format).
isFlareNetworkContract	When calling a C-chain contract, it returns true/false, depending if the contract was deployed by Flare.
parameters	When calling a C-chain contract, the method's parameters are returned. For types "addDelegatorP" and "addValidatorP", additional staking parameters are returned.
warnings	Warnings are returned for suspicious data (e.g., "Not official Flare contract").
messageToSign	Hash sent to the wallet to sign. Useful for confirming P-chain transactions.

When staking, the returned staking parameters are the following:

Parameters	Description
nodeId	Identifier of the validator node that you want to stake to.
startTime	Proposed starting time of the stake (in unix time).
endTime	Proposed ending time of the stake (in unix time).
validatorFee	Proposed node fee in % multiplied by 10000 (if you want to initialize staking on a validator node).