Simplest way to encrypt & decrypt ASCII texts

So, here’s the SECRET to a good Caeser salad — add some avocados. But this is not a food blog, so let’s talk about some ancient ciphers used in cryptography instead.

Substitution Cipher

A substitution cipher protect the data confidentiality by swapping the original characters to another random character in any text data.

The concept of encryption and decryption

For example, consider Alice sending text ‘ABC’ to Bob. Using any substitution cipher, Alice can encrypt the plaintext ‘ABC’ into a ciphertext like ‘DUA’ before sending it to Bob. Here, the character ‘A’ is replaced by ‘D’; ‘B’ is replaced by ‘U’ and C is replaced by ‘A’. Thus…

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Now everyone can work from home, securely (Part2/3)


Remote login allows users to connect to servers that are located in different networks from their local machine. Similar to how we use remote to control our devices even it is just few feet away (lazy people understand this); remote login allow us to work from anywhere while accessing data stored on remote servers in the company’s private networks.

Remote Login using TELNET

The simplest way to remote login is by using TELNET. TELNET is a basic protocol that opens TCP port 23 on the server for remote access. Each users are given a unique account that is password protected. …

Now everyone can work anywhere — Part1/3


My work shift starts at 8.30am, and I wake up 7.30am daily; so you can guess that I have one hour to get ready. Yet somehow I am always, still late to work. — Don’t get me wrong, I have a cosy office that make me feel less blue on each Mondays. Here’s a sneak peek of my work office.

An office I can call home

But with all the make-ups to put on before going on-air; to the artisan coffee I need to sip before I am human again, plus the commute time to work; I normally arrived at the office 1–2 hours late. But…

Hello, are you there?


Ping is a network utility to check network connectivity to a target destination. Ping is built-in on Windows, Linux and MAC OS. Ping operates based on the Internet Control Message Protocol (ICMP). It is commonly used to find out whether a destination host is reachable or not.


In this quarantine period, people stay at home during the lockdown restrictions. After spending countless day binge watching Netflix, you suddenly miss your friends. The natural thing to do is to reach out to our iPhone and call them — “Hey <insert weird name here>, are you still alive?”.

Machine also needs to…

The Definitive List to All the Materials You Need to Get an A

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I know what you did last summer


Nmap is one of the many network tools that make you feel powerful as a network admin or a penetration tester. Nmap is generally known as a port-scanning tool; but it can do much more than that. The core usage of Nmap is to scan for open ports on a target destination. Why is it powerful? — Well, that’s because most network applications run on some specific TCP/UDP port numbers; and port scanning allows us to get insights into what services that are running on a server, or in a network.

Over the…

Configuring Simple Static Route

Static Routes in Cisco Router

Now we will look at the simplest example to configure static routing given the network topology below. Take note that all IP addressing has been configured. So the only things left to do is to configure static routes.

Zoom in to Enlarge Networks

There are a few check lists before we start the configurations:

(A) Is routing needed? — there are two routers in the network; and LAN1 →LAN2 is 1 hop away; so YES(B) Should we configure static route or dynamic route?

There are more than one ways that leads to the destination

Intuition of Routing

The job of routers is to do routing. The end. If only routings were that simple. In this story, we will take a look at how routers actually do their job.

Now, imagine first time driving to a new mall. Intuitively, we use navigation apps like Google Maps or Apple Maps to point us to the right direction. Then we have this first world problems of which is the better route to take after we are offered several options.

Routing is similar to how we navigate in Google Maps

How to configure RIPv1

Day 1 at your new job as network engineer, and you got your first task. Configure routings on all routers in the topology below for full network connectivty.

Day 1 — Setup routings to connect all these LANs

Well, if we are to configure static routes here; this would be my first reaction.

That’s it I am out

Thankfully, we have dynamic routing protocols that simplify configurations of complex networks. Dynamic routing offload the trouble of having to find all destination networks manually; besides automatically detect bad paths and select best paths. So, what’s not to love about it?

In this story, we will demonstrate how…

Avocado Aun

I’m just a little boy, lost in the tech world. But remember, love is a riddle, and life with tech is more amazing than ever

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