topic Re: Hash a string : string to sha-256 in Talend Studio

Hash a string : string to sha-256

Anonymous — Tue, 24 Mar 2020 15:53:27 GMT

Hello,

to hash a string I found attached code. it's delivering a result but non significatives 0 (zeros on the left of the string) are not provided in the result ...

for exemple I get b1f3daebef8a4e237e7830579a8505378ce360106b69f55805f0b255e82637

but I was expecting 00b1f3daebef8a4e237e7830579a8505378ce360106b69f55805f0b255e82637

I can see that the code is manipulating a big integer ... that's probably the reason why zeros are eliminated ...

package routines;
import java.security.MessageDigest;
import java.math.BigInteger;
public class SHA {
public static String getMD5HashedPassword(String password, String salt) {
String sTH;
if(password == null) {
if(salt == null) sTH = "";
else sTH = salt;
}
else {
if(salt == null) sTH = password;
else sTH = password + salt;
}

try {
MessageDigest md5 = MessageDigest.getInstance("SHA-256");
md5.update(sTH.getBytes());
BigInteger hash = new BigInteger(1, md5.digest());
return hash.toString(16);
}
catch (Exception e) {
return null;
}
}
}

Re: Hash a string : string to sha-256

Anonymous — Tue, 24 Mar 2020 16:15:17 GMT

This code can hardly work. I guess the original version was intent to build MD5 hashes and these hashes are typically numbers.

The SHA-256 hash would be by far to large for a number therefore such hashes are typically Strings (like a guid).

    public static String buildSHA256Hash(String content) {
    	
    	if (content == null) {
    		return null;
    	}
    	// calculate hash
    	MessageDigest messageDigest;
		try {
			messageDigest = MessageDigest.getInstance("SHA-256");
		} catch (NoSuchAlgorithmException e) {
			throw new RuntimeException("Digest Algorithm SHA-256 could not be found in this environment.", e);
		}
    	
		final byte[] result = messageDigest.digest(content.getBytes(Charset.forName("UTF-8")));
		
		// convert hash to requested encoding
		return Base64.encodeToBase64String(result);
    }

And here the Base64 class. This is a Talend Routine you should create:

To see the whole post, download it here
OriginalPost.pdf

Re: Hash a string : string to sha-256

manodwhb — Tue, 24 Mar 2020 16:18:26 GMT

Instead of bigint you need to convert into string. Or after the value you got you convert into sting add leading zeros.

Re: Hash a string : string to sha-256

Anonymous — Thu, 16 Apr 2020 15:20:31 GMT

Bonjour jlolling,

Sorry, but I am a beginner and do not know how to "use" the code you posted.

With the one I posted, I was calling it from a tmap to convert row3.In just giving it as an input and the hashkey in addition :

SHA.getMD5HashedString(row3.In , context.HashKey)

If I create the talend routine you recommended to me, how can I use it in a simple manner ?

regards
Damien

Re: Hash a string : string to sha-256

nar — Tue, 05 Apr 2022 16:42:01 GMT

Hi @DamienBlondel ,

Did you find the solution to this, I'm getting same issue with leading zeros, If you find the solution could you please help me on this.