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Lucas. D
Asked: 2020-09-14 09:48:33 +0800 CST 2020-09-14 09:48:33 +0800 CST

I get two different values ​​when converting a String to SHA1

  • 772

I have the following code with which I am testing how to encrypt passwords with SHA1. I have used adapted code from two different sources but both bring me different results. 

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import javax.xml.bind.DatatypeConverter;

public class Encriptacion 
{

    public static void main(String[] args) throws UnsupportedEncodingException {

        String password = "Lucas";

        try 
        {
            //da39a3ee5e6b4b0d3255bfef95601890afd80709
            MessageDigest md = MessageDigest.getInstance("SHA1");
            md.update(password.getBytes(), 0 , password.length());
            System.out.println(new BigInteger(1, md.digest()).toString(16));

            //CBEDE02E8C227684972AB1467409D98C0D0D5A5D
            MessageDigest msdDigest = MessageDigest.getInstance("SHA1");
            msdDigest.update(password.getBytes("UTF-8"), 0, password.length());
            password = DatatypeConverter.printHexBinary(msdDigest.digest());
            System.out.println(password);

        } 
        catch (NoSuchAlgorithmException ex) 
        {
            System.out.println("ERROR : ");
            ex.printStackTrace(System.out);
        }

    }

}

I do not know what is the reason why it brings me different results or what is the correct way to encrypt a password.

java

1 Answers

  1. Best Answer

    Both are correct and valid methods:

    YO)

        MessageDigest md = MessageDigest.getInstance("SHA1");
    md.update(password.getBytes(), 0 , password.length());
    System.out.println(new BigInteger(1, md.digest()).toString(16));

    II) 

        MessageDigest msdDigest = MessageDigest.getInstance("SHA1");
    msdDigest.update(password.getBytes("UTF-8"), 0, password.length());
    password = DatatypeConverter.printHexBinary(msdDigest.digest());
    System.out.println(password);

    You can use both methods, both are correct, in the case of your question, if they are in the same method it only ensures that when calling each one you must initialize your variable:

    password = "Lucas";

    this way you will get the desired result.

    As for the result da39a3ee5e6b4b0d3255bfef95601890afd80709you're getting, the reason is that the value of password is an empty String "".

    • 3