Amp

Off-Chain (Private)

Audited on 2020/05/31

No active critical issues

Summary

Executive Summary This report presents the results of our engagement with Flexa to review Amp Token and Flexa Collateral Manager. Flexa is a payment network, using smart contract and Amp collateral to facilitate off-chain payments. The review was conducted over the course of two weeks, from June 9, 2020 to June 19, 2020 by Shayan Eskandari and Valentin Wüstholz. A total of 15 person-days were spent. The review of the initial report fixes were performed from August 10, 2020 to August 14, 2020 by Shayan Eskandari.

Project

AMP Collateral Token

Ethereum

Issues (15)

	Low	Medium	High	Critical	Total
Not fixed	2	1	-	-	3
Fixed	4	6	2	-	12
Total	6	7	2	0	15

Contracts (11)

#	File Name
1	amp-contracts/partitions/PartitionsBase.sol
2	amp-contracts/erc1820/ERC1820Client.sol
3	flexa-collateral-manager/contracts/amp/IAmpTokensRecipient.sol
4	flexa-collateral-manager/contracts/amp/IAmpTokensSender.sol
5	flexa-collateral-manager/contracts/erc1820/ERC1820Client.sol
6	flexa-collateral-manager/contracts/FlexaCollateralManager.sol
7	amp-contracts/erc1820/ERC1820Implementer.sol
8	amp-contracts/Amp.sol
9	amp-contracts/codes/ErrorCodes.sol
10	flexa-collateral-manager/contracts/amp/IAmp.sol

#	File Name
1	amp-contracts/partitions/PartitionsBase.sol
2	amp-contracts/erc1820/ERC1820Client.sol
3	flexa-collateral-manager/contracts/amp/IAmpTokensRecipient.sol
4	flexa-collateral-manager/contracts/amp/IAmpTokensSender.sol
5	flexa-collateral-manager/contracts/erc1820/ERC1820Client.sol
6	flexa-collateral-manager/contracts/FlexaCollateralManager.sol
7	amp-contracts/erc1820/ERC1820Implementer.sol
8	amp-contracts/Amp.sol
9	amp-contracts/codes/ErrorCodes.sol
10	flexa-collateral-manager/contracts/amp/IAmp.sol

Amp

Summary

Issues (15)

Potentially missing nonce checknot_fixed/medium

Several fields could be declared immutablenot_fixed/low

Several fields could potentially be privatenot_fixed/low

Contracts (11)