secret codes

If you haven’t already started to write things down on a computer, or other electronic device, then you are going to soon. You are going to be doing it a lot at school and then later when you go to work. Grown ups are using paper and pens less and less these days.

You can and should learn a number of skills to make writing on electronic devices simpler and better. In my opinion one of the most important of these is to learn how to touch-type; to write quickly without making mistakes using all ten fingers of both hands across the whole keyboard. With practice it is possible to be able to write at almost the same speed as it does to think. This is very difficult to do when using a pen and paper, and my handwriting looks like a drunk spider has escaped across my page from an inkwell when I try to write at anything approaching this speed. We will talk about learning to touch-type another time.

In the same way that there are different types of real paper, there are also different types of electronic paper. Knowing which kind to use is another useful trick, so that is what I am going to talk to you about today. Real paper can be shaped differently, have different thicknesses, and be of different colours. It may respond in unusual ways to some types of pen or pencil. Writing on electronic devices doesn’t involve paper, of course, but there is a choice of what software programme to use. Each allow you to write words in your alphabet of choice but they get to that result by means that are not the same. They record electronic writing in different file formats. You could think of files as electronic paper. Often these sheets of electronic paper are not readable by any other software. This is a problem if you want to use more than one device - such as a computer, a phone, a tablet, or a web-based word processor - to write on the same bit of electronic paper. Imagine only being able to use one type of pen on a piece of paper! Worse than this, the software applications you use today might not necessarily be around in five, ten or fifteen years from now. The homework you finish this year might not be able to be read again by the time you have left school and may be lost forever. OK maybe that’s not so terrible, but you get the idea; if you are bothering to keep your electronic documents then you want them to be readable in the distant future.

So my suggestion to avoid these problems would be to use text files. This type of electronic paper is just about the smallest and simplest type you could use. You can recognise text files because they have a .txt at the end of their name. Text files only include information about the letters, numbers and other symbols that you can see and so they only take up a small space on your device’s filing system or memory. Small is good when it concerns disk space and sharing files. How small are they? Well the text file I created writing this blog post was just 8 kilobytes. The same amount of words in a word processor software file was 459 kilobytes. The text file was 57 times smaller! Most applications and software can open text files because they are so simple. This makes it possible to use multiple devices to write on the same sheet of electronic paper, and it means that they will be readable a long way into the future by newer electronic devices. For those reasons you want to use this type of file above all others if you can.

The downside of using text files as digital notepaper is that they can’t do a lot. They are text and nothing else. All the extra stuff that people do with their writing using their word processors can’t be recorded in a text file. For example, making some text bold or writing a list of items with those items automatically numbered. But then a few years ago something changed. You couldn’t do those things with text files until something called markdown came along and changed things for the better.
Markdown is a way of writing that uses regular text file-friendly characters to put back in the formatting and other stuff that you can’t normally have in plain text files. It uses special marks amongst normal writing that a computer programme understands as being instructions about what to do with parts of the text. These marks don’t get in the way and still allow the text to be read easily by humans. It is very simple to use and, because you are going to use text files as your electronic paper of choice for all the reasons I’ve suggested you should, you should learn some basic markdown to help yourself in the years to come.

A simple example of how to use markdown would be to show you how to make a small amount of text appear bold. You do this by putting two asterisks ** at the beginning of the text selection and then another two asterisks at the end. So if I want to make these words bold, then I put two asterisks either side like this: **these words**. Any computer writing program that understand markdown - some don’t but many new ones do - will know that this is the instruction to make these words go bold. Instead of two asterisks you could use two underscore characters __ to do the same thing.
Another example of markdown is creating bulleted lists. If you create a list with asterisks, dashes or plus signs for every point, a markdown-friendly software programme will turn that into a proper bulleted list like this:

• Item one
• Item two
• Item three

I made the above list by simply typing this:

- Item one
- Item two
- Item three

The software I am using automatically turned the dashes into round bullet points.

There are lots more things that markdown can do. Take a look at the website of John Gruber, who invented it. If you want more then another clever chap created more types of special mark that can be used by lots of apps and programmes to create tables, citations, and other things you might need when you are a bit older and maybe doing a college degree. His name is Fletcher Penney and his website about his special marks, called MultiMarkdown, can be found here.

That is enough information for you to know the basics of what markdown is and know where to find out more about it. I can’t teach you much more other than to say that the best way to learn the special signs that make text files more useful is to start using them yourself and play with them to see what they can do.

The last thing I will do is to mention some software that can understand markdown in text files. I use a Mac and my favourite markdown editor is Byword. It also has an iOS application for iPads and iPhones. IA Writer and Writeroom do similar things I’m told. I heard that WriteMonkey is a solid bit of software for writing markdown on the PC but I’ve not used it myself. The Day One journal/diary Mac software - which is the best way I’ve seen to write an electronic diary, by the way - and iOS app understands markdown too. If you want to use a web-based writer then I’ve successfully used Dillinger although the saving of files somewhere such as in my dropbox folder was a bit tricky to understand at first. There are other markdown-understanding web word processors around I’m sure.

I am very glad that I learned how to use markdown with plain text files this year, and I’m sure that I will be using this way of writing on electronic devices for many years to come. I’m sure if you investigate it and get the hang of it that you will be doing the same too.

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secret codes

Why Do People Need Secret Codes?

Imagine you have a secret you want to tell your best friend, but nobody else. Perhaps last night you discovered you could fly. If everyone found out they would ask you lots of boring questions like, “What does my house look like from the sky?”, and your Dad would want your help cleaning out the gutters of the house. Yuk. Stuff like that.

If you were alone with your best friend in the same room then sharing the secret would be easy to do, but if he or she was somewhere else, or you were not alone, that would be more tricky. Somehow you would need to send the secret to that person in a way that only they could understand it. How could you do that?

You could make up your own special language that only the two of you could understand, but creating a brand new language would be very hard work and would take up a lot of time and practice; years probably. All that effort just in case one day you need to share a secret. That’s quite extreme.

How Secret Codes Work

A simpler way would be to use your normal language, but wrap up the message in a secret code. That would be a bit like sending a letter in a locked envelope. If you gave your best friend, and only your best friend, the key to unlock the envelope before you sent the message, then only he or she would be able to open it and know its true meaning. This is how all secret codes work.

I’m going to teach you a few new words. A secret code can also be called a cipher. Its pronounced ‘si-fer’. The original message in your language is called the plaintext. The message written in secret code is called the ciphertext. The act of turning a message into the coded message is called encryption; you encrypt the message. The act of turning the coded message back into the normal message is called decryption; you decrypt the coded message. The exact way encryption and decryption works is called the key for that particular code.

An Example: The Caesar Cipher

The best way to explain how this works is to show you. Let’s use a real secret code that was used a long time ago. It’s called the Caesar cipher, and is named after the famous Roman general, Julius Caesar, who used this way of encrypting his important letters, such as commands to his soldiers on the battlefield, so that his enemy wouldn’t understand them if they found them.

Let’s imagine that you want to send your friend the message “I can fly.”. The way this particular cipher works is that it swaps each letter in the message to a different letter in the alphabet to make it look like nonsense. The Caesar cipher transforms each letter into the letter 3 places further up the alphabet. They key to this code is +3. Other types of cipher transform letters in different ways to do the same thing. Our plaintext message is icanfly when written with no spaces inbetween. Now let’s encrypt the message. The table below shows how that transformation works for each letter of the alphabet using the Caesar cipher:

After encryption the message reads “MFDQIOB”.  That doesn’t mean anything to most people, does it? But to your friend, who knows what you have done, it does. When they receive the message they know they need to do the opposite transformation to be able to read it. In this case, they will need to change each letter in the ciphertext to the letter 3 places before it in the alphabet and then put the gaps back in sensible places so that the message makes sense:

So your friend will turn MFDQIOB into icanfly and then understand that you have cracked the ability to fly.

There are lots of ways of turning plaintext into ciphertext and back again. The history of secret codes is interesting on its own, but one of the most wonderful things about it is that nearly 80 years ago some British people who were trying to break some secret codes that they didn’t have the keys for created the World’s first computers to help them. I’ll tell you more about that in my next blog post.

EBHEBH

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