Java SHA-1 Hash用法及代碼示例

// Java program to calculate SHA-1 hash value 
  
import java.math.BigInteger; 
import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
  
public class GFG { 
    public static String encryptThisString(String input) 
    { 
        try { 
            // getInstance() method is called with algorithm SHA-1 
            MessageDigest md = MessageDigest.getInstance("SHA-1"); 
  
            // digest() method is called 
            // to calculate message digest of the input string 
            // returned as array of byte 
            byte[] messageDigest = md.digest(input.getBytes()); 
  
            // Convert byte array into signum representation 
            BigInteger no = new BigInteger(1, messageDigest); 
  
            // Convert message digest into hex value 
            String hashtext = no.toString(16); 
  
            // Add preceding 0s to make it 32 bit 
            while (hashtext.length() < 32) { 
                hashtext = "0" + hashtext; 
            } 
  
            // return the HashText 
            return hashtext; 
        } 
  
        // For specifying wrong message digest algorithms 
        catch (NoSuchAlgorithmException e) { 
            throw new RuntimeException(e); 
        } 
    } 
  
    // Driver code 
    public static void main(String args[]) throws 
                                       NoSuchAlgorithmException 
    { 
  
        System.out.println("HashCode Generated by SHA-1 for:"); 
  
        String s1 = "GeeksForGeeks"; 
        System.out.println("\n" + s1 + ":" + encryptThisString(s1)); 
  
        String s2 = "hello world"; 
        System.out.println("\n" + s2 + ":" + encryptThisString(s2)); 
    } 
}