Down to digits

Cryptography’s long history of keeping secrets points to the field’s bright future

Though cryptography has existed for thousands of years, its modern applications involve safeguarding everything from credit card information to national secrets.
Though cryptography has existed for thousands of years, its modern applications involve safeguarding everything from credit card information to national secrets.
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Code breaking isn’t just for modern day technology. Though not necessarily used to pass secret messages, evidence of early cryptography has been found among ancient ruins.
Code breaking isn’t just for modern day technology. Though not necessarily used to pass secret messages, evidence of early cryptography has been found among ancient ruins.
Photo: 

For the past six years, Ben Goodman has been playing a numbers game.

Goodman, Sci ’13, created his first code-breaking program in grade 12. It successfully translated regular language, called plaintext, to coded language, called cyphertext, and vice versa.

The program eliminated the use of a key — a system used to decode encrypted language.

“I wouldn’t say [it was] astonishing,” he said. The engineering physics student has been interested in cryptography since high school.

“It’s a very cool field. It’s always changing,” he said. “It branches into a lot of other fields in math and even physics.”

As the practice of writing and solving codes — rules that determine how to disguise information — cryptography has other uses as well.

In modern times, it’s made things like credit card transactions possible. Before that, though, it was a component in the Allies’ win of World War II.

Cryptologists on the Allied side were able to crack the German military’s secret codes, encrypted by the Enigma machine.

“The reason this is so important is that the Germans didn’t know the code had been broken so they continued to use the Enigma machine to code their radio transmissions,” history professor Allan English said.

These transmissions helped the Allied forces gain intelligence about the other side.

“Sometimes the information proved to be very valuable in terms of campaigns and operations in the war because they knew what the Germans were going to do,” he said.

According to English, the Enigma machine involved a method of encryption that had never been seen before.

“The Enigma machines that the Germans built were highly complex and very difficult to decrypt,” he said.

While the Enigma machine’s codes could initially be cracked, English said, the battle for intelligence was a continuous one.

“What normally happens is that codes get broken and then the enemy changes the code and then the codes get broken — it’s an ongoing thing,” he said. “What you need is a really robust intelligence section.”

With the mass amounts of digital information in the world today, he said the main difficulties may come from making meaning from mess.

“It’s very easy nowadays to collect information,” English said. “The hard part is making sense of it.”

With advancing computer technology, English said encryption has become a way to merely slow the enemy down instead of stopping them altogether.

“Sometimes it doesn’t matter if you can keep a thing secret forever,” he said. “You just have to keep it secret long enough so that when the info comes out, it’s not as worth it to the other side.”

However, the quest to make better secret-keeping technology still continues.

When a new coding technology called public key encryption emerged in 1976, it made an impression on young cryptography enthusiasts everywhere.

School of Computing Director Selim Akl was one of them.

“It was very simple and extremely hard to break,” he said.

For security-minded people everywhere, the new system helped keep their peace of mind.

“We all care about our privacy. We all care about the security of our data,” he said. “Who knows what people can do with information about you that you don’t want revealed?

“That is the main motivation for working in cryptography: individual privacy.”

It’s something that brings students to the field, he said, along with images that are closer to Hollywood’s idea of code breaking.

“There’s always this spying James Bond aspect to it,” Akl said.

It’s more than that, though.

“Once they see the simplicity and beauty and elegance of the current approaches compared to the messiness of the old approaches, they love it.”

Public key encryption (PKE) involves the use of two keys — systems used to interpret coded messages. By using a publicly displayed key and a private key, two people could securely exchange information.

It’s a far cry from older encryption technology that used a single key.

Akl said it wasn’t the most effective way of securing information.

“The moment you discovered the key, the system was broken essentially,” he said.

The core of cracking this old system involved statistics, the method utilised by cryptologists during World War II to solve the German military’s Enigma machine code.

“You could break it by watching over time many messages. You could gather statistics,” he said.

With these conventional systems, Akl said there was a lower guarantee for security.

“Using the key repeatedly is the principle weakness,” he said.

Though single key systems aren’t as prominent anymore, PKE remains in use today. It’s used by banks and credit card companies to safeguard their clients’ information.

Akl said this still doesn’t guarantee 100 per cent security.

“All cryptosystems are breakable, except for one,” he said.

That system, called the one-time pad, is used by militaries and political institutions worldwide. It involves a list of 500 keys where each one is used once.

By systematically using one key per message, two parties can make it difficult for someone to understand their code.

Still, the system isn’t the most efficient, Akl said.

“It’s extremely cumbersome because you have to always meet in a secret place to exchange this list of keys.”

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