Update README.md

unit09_future/lab/README.md

@@ -97,6 +97,94 @@ Once we deploy our contact, we can use Remix to test it. In the following we see
 
 Test the other functions, and check that they work.
 
+## Hashing
+Open Zeppelin is open-source Solidity library that supports a wide range of functions that integrate into smart contracts in Ethereum. In the following we will implement a number of standard hashing methods, alongside a Base64 integration from Open Zeppelin:
+
+```Solidity
+pragma solidity ^0.8.0;
+import "@openzeppelin/contracts/utils/Base64.sol";
+import "@openzeppelin/contracts/utils/Strings.sol";
+
+contract Hashit {
+
+    function getKeccak256(string memory str) public pure returns(bytes32){
+        return keccak256(abi.encodePacked(str));
+    }
+
+    function getSha256(string memory str) public  pure  returns (bytes32) {
+        return sha256(abi.encodePacked(str));
+    }
+
+    function getBase64(string memory str) public pure returns(string memory){
+        return Base64.encode(abi.encodePacked(str));
+    }
+
+    function getStringHex(uint256 str) public pure returns(string memory){
+        return Strings.toHexString(str);
+    }
+
+    function getString(uint256 str) public pure returns(string memory){
+        return Strings.toString(str);
+    }
+}
+```
+
+With this, we get a number of solidity code integrations that enhance smart contracts:
+
+The integration is fairly simple, and where we just pick the required solidity file integration (after reviewing it, of course). In the following we integrate with Base64 and Strings:
+
+```
+import "@openzeppelin/contracts/utils/Base64.sol";
+import "@openzeppelin/contracts/utils/Strings.sol";
+```
+
+There are certain standard hash functions that integrate into Solidity. These include keccak256() and sha256():
+
+```
+    function getKeccak256(string memory str) public pure returns(bytes32){
+        return keccak256(abi.encodePacked(str));
+    }
+
+    function getSha256(string memory str) public  pure  returns (bytes32) {
+        return sha256(abi.encodePacked(str));
+    }
+```
+
+We can then create our smart contract in Remix [here], and compile the contract:
+
+![here](https://asecuritysite.com/public/gan05.png)  
+
+Now we can start our local blockchain with Ganache:
+
+![here](https://asecuritysite.com/public/estate45.png)  
+
+And then deploy our smart contact:
+
+![here](https://asecuritysite.com/public/estate46.png)  
+
+We then see that this has cost one of the accounts some amount of gas:
+
+![here](https://asecuritysite.com/public/estate47.png)  
+
+And then we see we have a contract:
+
+![here](https://asecuritysite.com/public/estate48.png)  
+
+Now we can go ahead and test the contract:
+
+![here](https://asecuritysite.com/public/estate49.png)  
+
+In this case we see that the Base64 string for “hello” is “aGVsbG8=”, and that the Keccak-256 hash for “hello” is “0x1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8”. You can test this [here]:
+
+![here](https://asecuritysite.com/public/estate50.png)  
+
+And [here] for Base64:
+
+![here](https://asecuritysite.com/public/estate51.png)  
+
+Now go ahead and test each of the methods, and prove that they work.
+
+
 ## Light-weight crypto
 ### L1	
 In many operations within public key methods we use the exponential operation: