Cryptocurrency is decentralized and not beholden to any 3rd party authorities, which increases token owner autonomy. However, lacking a 3rd party to monitor transactions, flag suspicious behaviour, and freeze accounts leaves token owners vulnerable to complete asset liquidations if their private key, seed phrase, or wallet login process is exposed to hostile actors. Furthermore, many non-native web3 users are not prepared to take full responsibility for their onchain assets.
The ERC20SpendingLimit token provides the convenient security protections of traditional banking, but implements through an ERC20 smart contract to keep token owners' assets decentralized and autonomous beyond the reach of any 3rd party authority.
These extended limits are enforced through the user's customizable configuration, which can also be set to default parameters:
spent = sum of `_transfer` during `allowancePeriod`
spendingLimit = spending limit during `allowancePeriod`
allowanceStart = allowance start-time, set with `spendingLimit`
allowancePeriod = allowance period before `spent` is reset
approvalPeriod = allowance period for token approvals before expiration
decayInterval = decay rate half-life of token approvals
approvalStart = allowance expiration of token approvals
---
struct UserConfig {
uint256 spent;
uint256 spendingLimit;
uint256 allowanceStart;
uint256 allowancePeriod;
uint256 approvalPeriod;
uint256 decayInterval;
mapping(address => uint256) approvalStart;
}
Foundry Book: https://book.getfoundry.sh/getting-started/installation
After Foundry is installed and this repo has been cloned, run the following commands:
forge build
forge test
All ERC20 functionality is assumed. Any address can recieve ERC20SpendingLimit tokens, however outbound spending cannot be executed until the owner of the tokens sets up their UserConfig, which enforces their spending limit, allowance period, approval period, and approval decay rate for individual approvals. The user can opt out of any or all limits by setting their configuration to infinite values (max int = 2**256 - 1).
Forge Verify-Contract: https://book.getfoundry.sh/reference/forge/forge-verify-contract
Token Verification
forge verify-contract --chain <ID> --flatten --watch --compiler-version "v0.8.11+commit.d7f03943" <CONTRACT_ADDRESS> ERC20SpendingLimit $BLOCK_EXPLORER_KEY
MIT License
Copyright (c) 2023 Hunter King
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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