SC to verify an address and accept an invitation

packages/zevm-app-contracts/contracts/zeta-points/Reference.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.7;
+
+contract Reference {
+    /* An ECDSA signature. */
+    struct Sig {
+        uint8 v;
+        bytes32 r;
+        bytes32 s;
+    }
+
+    mapping(address => mapping(address => uint256)) public invitations;
+
+    error InvalidInvitation();
+    event Invitation(address indexed inviter, address indexed invitee);
+
+    function validateInvitation(address inviter, address invitee, Sig calldata sig) private view {
+        bytes32 payloadHash = keccak256(abi.encode(inviter, invitee));
+        bytes32 messageHash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", payloadHash));
+
+        address actualSigner = ecrecover(messageHash, sig.v, sig.r, sig.s);
+        if (inviter != actualSigner) revert InvalidInvitation();
+    }
+
+    function acceptInvitation(address inviter, Sig calldata sig) external {
+        if (invitations[inviter][msg.sender] != address(0)) revert InvalidInvitation();
+        validateInvitation(inviter, msg.sender, sig);
+        invitations[inviter][msg.sender] = block.timestamp;
+        emit Invitation(inviter, msg.sender);
+    }
+}

packages/zevm-app-contracts/contracts/zeta-points/Register.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.7;
+
+contract Register {
+    mapping(address => uint256) public verified;
+
+    event UserVerification(address indexed user, uint256 timestamp);
+
+    function verify() external {
+        verified[msg.sender] = block.timestamp;
+        emit UserVerification(msg.sender, block.timestamp);
+    }
+
+    function isVerified(address addr) external view returns (bool) {
+        return verified[addr] > 0;
+    }
+
+    function whenVerified(address addr) external view returns (uint256) {
+        return verified[addr];
+    }
+}