SslServerApplication.java

package com.snhu.sslserver;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
public class SslServerApplication {

	public static void main(String[] args) {
		SpringApplication.run(SslServerApplication.class, args);
	}
}

@RestController
class ServerController {
    
    // Function to calculate the SHA-256 checksum
    public String calculateHash(String data) throws NoSuchAlgorithmException {
        // Instantiate the SHA-256 MessageDigest
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        
        // Hash the data string into a byte array
        byte[] hash = digest.digest(data.getBytes(StandardCharsets.UTF_8));
        
        // Convert the byte array into a readable Hex string format
        StringBuilder hexString = new StringBuilder();
        for (byte b : hash) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }
        return hexString.toString();
    }

    @RequestMapping("/hash")
    public String myHash() throws NoSuchAlgorithmException {
        // Your unique data string combining the static requirement and validation details
        String data = "Rebecca Scranton - Hello World Check Sum!";
        
        // Generate the checksum
        String checksum = calculateHash(data);
        
        // Return the formatted HTML output for the browser
        return "<p><strong>Data:</strong> " + data + "</p>" +
               "<p><strong>Name:</strong> Rebecca Scranton</p>" +
               "<p><strong>Checksum Value (SHA-256):</strong> " + checksum + "</p>";
    }
}