├── .gitignore
├── README.md
└── contracts
    └── Algoz.sol


/.gitignore:
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1 | build
2 | node_modules


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/README.md:
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1 | # Algoz Contracts
2 | 


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/contracts/Algoz.sol:
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 1 | // SPDX-License-Identifier: MIT
 2 | pragma solidity >=0.8.4;
 3 | 
 4 | import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
 5 | import "@openzeppelin/contracts/utils/math/SafeMath.sol";
 6 | 
 7 | contract Algoz {
 8 |     using ECDSA for bytes32;
 9 |     using ECDSA for bytes;
10 | 
11 |     mapping(bytes32 => bool) public consumed_token;
12 |     address public token_verifier;
13 |     bool public verify_enabled;
14 |     uint public proof_ttl;
15 | 
16 |     constructor(address _token_verifier, bool _verify_enabled, uint _proof_ttl) {
17 |         require(_proof_ttl>0, "AlgozInvalidTokenTTL");
18 |         token_verifier = _token_verifier;
19 |         verify_enabled = _verify_enabled; // should be true if the contract wants to use Algoz
20 |         proof_ttl = _proof_ttl; // ideally set this value to 3
21 |     }
22 | 
23 |     function validate_token(bytes32 expiry_token, bytes32 auth_token, bytes calldata signature_token) public {
24 |         if(!verify_enabled) return; // skip verification if verify_enabled is false
25 |         require(!consumed_token[auth_token], "AlgozConsumedTokenError"); // verify if the token has been used in the past
26 |         require(SafeMath.add(uint256(expiry_token), proof_ttl) >= block.number, "AlgozTokenExpiredError"); // expire this proof if the current blocknumber > the expiry blocknumber
27 |         require(abi.encodePacked(expiry_token, auth_token).toEthSignedMessageHash().recover(signature_token) == token_verifier, "AlgozSignatureError"); // verify if the token has been used in the past
28 |         consumed_token[auth_token] = true;
29 |     }
30 | }
31 | 


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