Quick-tips

SSH Tunneling

ssh -f -N -L local-port:host:remote-port user@personal-sever

-N instructs OpenSSH to not execute a command on the remote system
-f tells ssh to go into the background just before it executes the command
-L tells how the traffic through person-server to tunnel to local machine as in local-port:host:remote-port

example usage: ssh -f -N -L 9443:10.0.69.42:9443 rajith@54.124.15.43

Traffic from 10.0.69.42 port 9443 will be tunneled via 54.124.15.43 to my local machine under port 9443

Java Cryptography Extension (JCE) unlimited strength jurisdiction policy

How install

• Go to Oracle Java SE download page http://www.oracle.com/technetwork/java/javase/downloads/index.html
• Under additional resources you will find "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files"
• Download the version that matches your installed JRE http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html
• Uncompress and extract the downloaded file
• Follow the README file there.
• Copy local_policy.jar and US_export_policy.jar to the $JAVA_HOME/jre/lib/security (Note: these jars will be already there so you have to overwrite them)

How to test

Execute the following,

import javax.crypto.Cipher;
import java.security.NoSuchAlgorithmException;

public class Main {

    public static void main(String[] args) throws NoSuchAlgorithmException {
        int maxKeyLen = Cipher.getMaxAllowedKeyLength("AES");
        System.out.println(maxKeyLen);
    }
}

Without the JCE unlimited strength policy files the result would be 128. if the installation is successful the result will be 2147483647