Current Affairs Fans of codes and secret ciphers attend special conference in Prague

Stefano Cavagnetto, photo: Prague College A trailer for the successful 2001 film Enigma, loosely based on the efforts of British and Polish code-breakers at Bletchley Park - the headquarters of Britain's top secret wartime code-breaking facility. Enigma and other wartime and later Cold War encryption machines have long served as a source of fascination to both military historians and mathematicians, including Stefano Cavagnetto, head of the School of Computing at Prague College, and the man behind the conference.

"I think the fascination is related to the fact that it's something hidden, that we don't see, that people can't perceive, but is there and we know it's there, and you know people know it's there, and there is always the mystery around that. To a wider audience that's the main interest. There is something hidden around, and so on and so on."

Detlev Vreisleben The conference covered everything from the Enigma machine - including a computer recreation called E-Enigma - to how Czechoslovakia's intelligence service communicated with their secret agents. And also, this... ...for decades, ever since the height of the Cold War, shortwave radio enthusiasts have come across these odd, nursery rhyme-like tunes followed by strange, disembodied voices reading out apparently meaningless reams of numbers. They're called the number stations, and they're presumably used by the world's intelligence services to send clandestine messages to agents in the field - I say presumably because their content has never been deciphered and no government has ever officially admitted their existence. Detlev Vreisleben is a retired telecommunications engineer from Germany, attending the conference to speak about the secret service communications of East and West Germany.

"If you want to send a message to an agent, you transfer the text to numbers, and then you add a random number series, and send the sum of it. And the agent has the same random number series, and he subtracts it and gets a text. It's a safe method if it's only used once."

Data encryption and encoding technology is increasingly used by all of us - each time we log on to our online bank accounts or make what we assume is a secure transaction. Doug Hajek is the director of the Prague College.

Doug Hajek "We all put trust in our banks. Some banks have more secure systems than others, but as we were developing the conference some information came to light that such simple things as even deeply secure banking information is not secure at all. If people can get access to the computer and adjust the voltage levels going into to the central processor, and over time, with a lot of hardcore mathematical analysis of the results of those changes in voltages, they can actually get any information they want. So yeah, it has really huge implications."

Some rather disturbing claims there about the security - or not - of our encoded computer data, data that's used more and more to control how we behave. Whether it's the mysterious number stations or online banking, encryption has become a simple fact of our everyday lives.