From f9dbe7c474b39910d0e1a8a2bd9b852339dff70a Mon Sep 17 00:00:00 2001
From: 0xBeWater <shenzhimeng@users.noreply.github.com>
Date: Wed, 16 Oct 2024 17:19:21 +0800
Subject: [PATCH] 2024.10.16

---
 ruoshui.md | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/ruoshui.md b/ruoshui.md
index 9bd3a0de..438af2dc 100644
--- a/ruoshui.md
+++ b/ruoshui.md
@@ -3633,4 +3633,83 @@ contract ERC4626 is ERC20, IERC4626 {
     }
 }
 ```
+### 2024.10.16
+[EIP712 类型化数据签名](https://eips.ethereum.org/EIPS/eip-712) 比 [EIP191 签名标准(personal sign)](https://eips.ethereum.org/EIPS/eip-191) 要高级安全一些，会展示签名消息的原始数据，用户可以在验证数据符合预期之后签名。
+
+签名验证
+
+```solidity
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.21;
+
+import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
+
+contract EIP712Storage {
+    using ECDSA for bytes32;
+
+    bytes32 private constant EIP712DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
+    bytes32 private constant STORAGE_TYPEHASH = keccak256("Storage(address spender,uint256 number)");
+    bytes32 private DOMAIN_SEPARATOR;
+    uint256 number;
+    address owner;
+
+    constructor(){
+        DOMAIN_SEPARATOR = keccak256(abi.encode(
+            EIP712DOMAIN_TYPEHASH, // type hash
+            keccak256(bytes("EIP712Storage")), // name
+            keccak256(bytes("1")), // version
+            block.chainid, // chain id
+            address(this) // contract address
+        ));
+        owner = msg.sender;
+    }
+
+    /**
+     * @dev Store value in variable
+     */
+    function permitStore(uint256 _num, bytes memory _signature) public {
+        // 检查签名长度，65是标准r,s,v签名的长度
+        require(_signature.length == 65, "invalid signature length");
+        bytes32 r;
+        bytes32 s;
+        uint8 v;
+        // 目前只能用assembly (内联汇编)来从签名中获得r,s,v的值
+        assembly {
+            /*
+            前32 bytes存储签名的长度 (动态数组存储规则)
+            add(sig, 32) = sig的指针 + 32
+            等效为略过signature的前32 bytes
+            mload(p) 载入从内存地址p起始的接下来32 bytes数据
+            */
+            // 读取长度数据后的32 bytes
+            r := mload(add(_signature, 0x20))
+            // 读取之后的32 bytes
+            s := mload(add(_signature, 0x40))
+            // 读取最后一个byte
+            v := byte(0, mload(add(_signature, 0x60)))
+        }
+
+        // 获取签名消息hash
+        bytes32 digest = keccak256(abi.encodePacked(
+            "\x19\x01",
+            DOMAIN_SEPARATOR,
+            keccak256(abi.encode(STORAGE_TYPEHASH, msg.sender, _num))
+        )); 
+        
+        address signer = digest.recover(v, r, s); // 恢复签名者
+        require(signer == owner, "EIP712Storage: Invalid signature"); // 检查签名
+
+        // 修改状态变量
+        number = _num;
+    }
+
+    /**
+     * @dev Return value 
+     * @return value of 'number'
+     */
+    function retrieve() public view returns (uint256){
+        return number;
+    }    
+}
+```
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