But getting information back to your allies can be harder than getting the information in the first place. You have two choices: either make direct contact with your allies, or leave the information somewhere you know that they will look. Morse Code Any message you send out has to be clear for your allies to decode. Morse code is a reliable system as the signal is made up of only three parts - a long 'on', the dash; a short 'on', the dot; and an 'off' signal. It can be transmitted over large distances by a number of methods, including radio, tapping on pipes, or light. If you and your contact both have transmitting and receiving devices, then you can send signals to each other. Using light to transmit Morse code gives you a cheap receiving device - your eyes. You can send messages across many miles, particularly if you have a pair of binoculars to magnify the signal. Both you and your contact will need a Morse code table so that you can encode and decipher your messages. Decide on the message that you want to send, then using the Morse code table send it as a series of long and short flashes. As a light source at night, you could use a torch that you can switch on and off rapidly, or cover with a black piece of card. On a sunny day, you could use a small hand-held mirror or even the shiny surface of a CD to reflect light in the right direction. The receiver, unless they have managed to memorise the table, will have to note the series of flashes down on paper to decode later. How does it work? Morse code was devised in the 1830s when the telegraph was invented allowing electrical signals to be transmitted by wires. A simple system of dashes and dots and gaps makes a robust way to transmit information - even if the signal is not very clear at the far end, there should be enough difference between the three types of signal to distinguish between them, so the message remains unscrambled. The choice of dashes and dots to signal a letter is related to how often they are used in the English language. Frequent letters get a short code, such as E with just one dot. Less used letters have to use a longer code, Z has two dashes then two dots. Although Morse code is a code, it's one that everyone has the key to, so if anyone intercepts the signal they will be able to understand it. To make a transmission secure they encode the signal using another code that only the sender and receiver know. Spies can also use radio transmission, but security agents may be scanning the frequencies on the lookout for suspicious transmissions. Even if they cannot decode the message, they could still home in on the transmission location and capture the spy. To avoid this, both sender and receiver arrange to broadcast on a varying sequence of frequencies, changing after a pre-determined time. Another way of avoiding detection is to pre-record the information and then send it in a high information 'burst' transmission, rather than in real time. This drastically reduces the length of the broadcast, making it far harder to spot. Microdots Rather than using a code, which may draw attention to itself, you could simply hide your secret information in an innocent looking document and send it by normal routes. Even if suspicious security staff inspect the document, they will only see a boring old report about pigeon breeding, or whatever, and miss the covert contents. Microdots work by shrinking words or letters until they become unnoticeable in a standard sized document. The receiver than magnifies the dots to read your message. You can use the word processor package on a computer to shrink the font size of individual letters until they are barely noticeable, then hide them in a normal text as full stops. Version One Write a boring article, then type out your secret message. Using the format command on your word processor, select the whole of your message and change its font size. If your normal font size is 12, make the shrunken font size about 1 or 2. You may find that you want to change the font of the shrunken letters as some fonts are more condensed than others. Now go through the document, and replace each full stop with one of the shrunken letters by cutting and pasting them in. You may need to fiddle with their size or alter them to bold or italic to make them appear as similar to full stops as possible. Even if your message is finished half-way down the document, you may want to replace the rest of the full stops with random letters, just so they all look the same. Now print out the document and send the paper version to your contact. They will be able to read your message by looking at each full stop through a magnifying glass. Version Two This version has to be written, sent and unscrambled on a computer. This way you can hide the complete message in just one full stop. Write your message, then selecting the format command again shrink the font size to about 1 or 2. Now select character spacing, choose the condense command and make the writing as condensed as possible. This forces the letters to be typed over the top of each other. Email the innocent looking document to your contact who will be able to unscramble the full stop by highlighting the whole document, choosing the condense command and restoring the text to normal. Real spies used to use photography equipment to shrink down large amounts of text or pictures until they all fitted onto one full stop. This could then be blown up again by whoever received the message. Nowadays, you can hide a text message inside a computer image file, such as a JPEG, and send it over the Internet. Because an image file is very large, the information that forms the text is only a tiny part of the whole, and is very hard to spot - people think that you are only sending an innocuous picture. Telephones Establishing a secure two-way connection with an ally can be difficult, but it allows for rapid communication of data and is invaluable if plans have to be changed at the last minute. You will need two plastic drinking cups or tin cans, make sure they are empty and clean and a long piece of string or nylon twine. Pierce the bottom of the cups with a needle (the tins will need a skewer and hammer – be careful!). Thread the string through. Secure the string by taping a loop of it to the inside of the bottom of the cup. To work, the string has to be pulled tightly between the two cups. You and your ally can take turns to listen and speak to each other. To transmit, hold the cup up to your mouth and speak into it. (Or you could tap out a code instead for extra security!) To receive, hold the cup up to your ear. You may feel that you can now have a private conversation, but is your transmission secure? Enemy agents may be able to tap into the signal and listen to every word. By tying a third cup to the middle of the long piece of string, your enemies will be able to monitor your communications. As long as they stay silent, you may never know they are there. How does it work? Sound waves are vibrations that can be carried through the air and solid objects. When you speak into the cup, you cause air molecules to vibrate and the vibration is transferred to the cup and then the string. If the string is held taught, the vibrations can travel down the string to the second cup, where the vibrations set the cup vibrating and the cup causes the air to move! By tying a third cup to the string the vibrations in the string are divided between all three cups. It may seem rather obvious when someone ties a third cup to your telephone string but in real life phones are tapped all the time without people knowing. This is particularly true for mobile phones since the signal from your mobile phone can be picked up by anyone with the right equipment. Mobile phones transmit signals to the local receiving station, where they are retransmitted to a satellite or another base station. A spy can scan all the frequencies that the receiving station can pick up and so listen in to any phone call made in that area. Real spies try not to use mobile phones as they are very easily traced. Mobile phones are continually giving out signals to the nearest base station in readiness for any incoming or outgoing calls. If the enemy knows which phone a spy is using, they can trace the phone to its nearest base station. In a city, base stations can be as close as 100 metres apart meaning that tracing the position of the phone can easily lead to tracing the position of the spy. Interrogation Despite their best efforts spies may still get caught or come under suspicion. If you were headed for interrogation, how well would you be able to lie? And how would the enemy be able to tell if you were lying? Spotting a lie Try questioning your friends. Think up a set of questions and get them to purposely lie for some of the answers and see if you can spot the truth. Start off with easy questions like what they had for dinner last night, or when they last had a bath. Then try something more difficult, like who they fancy. Pay close attention to their body language when they are answering the questions. According to psychologists, hands on the face, especially the mouth, mean that someone is ‘covering’ a lie. They may shake their head when they are answering yes, or nod yes when they mean no. Crossing arms and legs is considered a protective instinct – are they protecting the truth? Watch their eyes – are they continually looking towards the door or window? Will they look you in the eye when answering? If they are not fully focused on their answer it could be a lie. How does it work? Lying makes people anxious and this has an effect on the body. The nervous system is affected by higher emotions producing physiological effects that can be detected. Their palms may begin to sweat; the pupils of their eyes constrict and their heart rate will increase. The way someone answers a question can also offer some indication of whether it’s the truth or not. Talking fast or mumbling is often a subconscious way of believing that the lie won’t matter. Being over friendly and smiling when replying can also be a dead give away. Spies are trained not to crack under interrogation but the best ones can also conceal the truth by controlling their body’s reactions. A spy under suspicion may be given a polygraph test to measure their heart rate, blood pressure, respiratory rate and how sweaty their hands are as they are asked a series of questions. By causing themselves pain whenever they answer a question – whether it’s the truth or not – the spy can confuse the results. The surge of chemicals through their body every time they bite their tongue or jab a drawing pin into their foot can swamp the body’s tell tale response to the lies. Other tricks include using antiperspirant on their hands and taking sedatives to reduce their respiratory and heart rates. receiving your instructions • gathering information • reporting back • spy box menu