Thread: hmac sha256

I'm using eclipse: there is no error but nothing shown on console.

I did some little changes and removed comments and tryed to print kSigning. Follows the code and error message. It seems that I'm not able to call the two methods inside the main.

Java code

package signature;

import org.apache.commons.codec.binary.Hex;


import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;


public class signing_key3a {
public static void main(String[] args)
{
String key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
String dateStamp="20180713T111300Z";
String regionName="eu-west-1";
String serviceName="iotdata";
String data="20180713";
String algorithm="HmacSHA256";

try
{
Mac HmacSHA256 =Mac.getInstance(algorithm);
SecretKeySpec kSecret = new SecretKeySpec(key.getBytes("UTF-8"), algorithm);
System.out.println(kSigning);

}
catch(Exception e)
{
e.printStackTrace();
}

}




static byte[] HmacSHA256( String data, String key) throws Exception

{
key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
data="20180713";
String algorithm="HmacSHA256";

byte[] key1=key.getBytes();

Mac mac = Mac.getInstance(algorithm);
mac.init(new SecretKeySpec(key1, algorithm));
return mac.doFinal(data.getBytes("UTF8"));
}


static byte[] getSignatureKey(String key, String dateStamp, String regionName, String serviceName) throws Exception
{
key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
dateStamp="20180713T111300Z";
regionName="eu-west-1";
serviceName="iotdata";
String algorithm="HmacSHA256";
byte[] kSecret = ("AWS4" + key).getBytes("UTF8");
String kSecret1=kSecret.toString();
byte[] kDate =HmacSHA256(dateStamp, kSecret1);
String kDate1=kDate.toString();
byte[] kRegion = HmacSHA256(regionName, kDate1);
String kRegion1=kRegion.toString();
byte[] kService = HmacSHA256(serviceName, kRegion1);
String kService1=kService.toString();
byte[] kSigning = HmacSHA256("aws4_request", kService1);

System.out.println( Hex.encodeHexString( kSigning));
return kSigning;
}

}

/code


MESSAGE

kSigning cannot be resolved to a variable

Finally I solved! Ipost the orrect code, perhaps it can help someone. There were two problems: the first was that I was not calling the methods inside the main, the second was that I should rename the variable kSigning inside the main to print it bacause the method rename just the value, not the variable. Thank you very much for your help!

 
package signature;
 
import org.apache.commons.codec.binary.Hex;
 
 
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
 
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
 
 
public class signing_key3a {
	public static void main(String[] args)  throws Exception
	{
		String key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
		String dateStamp="20180713T111300Z";
		String regionName="eu-west-1";
		String serviceName="iotdata";
		String data="20180713";
		String algorithm="HmacSHA256";
		//byte[] kSigning2 = getSignatureKey( key, dateStamp, regionName,  serviceName);
		HmacSHA256( data, key);
		try
		{
			//getSignatureKey( key, dateStamp, regionName,  serviceName);	
		Mac HmacSHA256 =Mac.getInstance(algorithm);
		SecretKeySpec kSecret = new SecretKeySpec(key.getBytes("UTF-8"), algorithm); 
		 //System.out.println(kSigning2);
			byte[] kSigning2 = getSignatureKey( key, dateStamp, regionName,  serviceName);
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
 
	}
 
 
 
 
		static byte[] HmacSHA256( String data, String key) throws Exception 
 
	{
		key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
		data="20180713";
		String algorithm="HmacSHA256";
 
		byte[] key1=key.getBytes();
 
		Mac mac = Mac.getInstance(algorithm);
	    mac.init(new SecretKeySpec(key1, algorithm));
	    return mac.doFinal(data.getBytes("UTF8"));
	}
 
 
	static byte[] getSignatureKey(String key, String dateStamp, String regionName, String serviceName) throws Exception 
	{
		   key="8cTZJ5chnb7YcUszssveBXZDTvvhhUFQd3YACxFp";
		   dateStamp="20180713T111300Z";
		   regionName="eu-west-1";
		   serviceName="iotdata";
		String algorithm="HmacSHA256";
		byte[] kSecret = ("AWS4" + key).getBytes("UTF8");
		String kSecret1=kSecret.toString();
		byte[] kDate =HmacSHA256(dateStamp, kSecret1);
		String kDate1=kDate.toString();
		byte[] kRegion = HmacSHA256(regionName, kDate1);
		String kRegion1=kRegion.toString();
		byte[] kService = HmacSHA256(serviceName, kRegion1);
		String kService1=kService.toString();
		byte[] kSigning = HmacSHA256("aws4_request", kService1);
 
		System.out.println( Hex.encodeHexString( kSigning));
		return kSigning;
	}
 
	}