Since about 1900 BCE, when unusual hieroglyphics were written on a nobleman’s tomb in Egypt, we’ve been inventing new forms of cryptography, or the art and science of keeping information secure. It turns out protecting information has been extremely important to humans for a long time, and – because we now share our personal data more than ever before – it’s a good time to look back and understand a bit about how we got here.
Here are some highlights of our cryptographic inventions over the past 2,500 years:
- The Scytale: Fighting wars has always been a big driver of innovation in cryptography. Around 500 BCE, Spartans who were trying to send secure messages during military campaigns wrapped a piece of parchment with a message around a cylinder called a scytale. To decrypt the message, the recipient had to have a cylinder of the same size. While it wasn’t the most sophisticated method by modern standards, it may have seemed pretty ingenious at the time.
- Head tattoos: Around the same time, Histiaeus of Meletus – a cruel Greek leaderseeking to revolt against the King of Persia – tattooed that conspiratorial message on a slave’s head, waited for his hair to grow back and sent him to another rebellious leader with instructions to start a rebellion. Although the King ultimately beat back the attack, the message itself seemed to work!
- The Caesar cipher: More than 2,000 years ago, Julius Caesar developed a simple system to send secure information to his troops. It was all about substituting certain letters for others, typically by shifting the letters by a predetermined number, according to researcher Nicholas McDonald. That algorithm is what we would call a cipher, and since Caesar’s invention, we’ve made cipher keys much more secure and advanced. Though it may sound obvious, if you want encrypt and decrypt information, you are going to have to choose a kind of cipher to do so.
- The Enigma machines: The cipher machines, famous for their use by the Nazis in World War II, were made up of electronically connected rotors. Although the messages, which were deciphered with a set of daily keys, were hard to crack, the whole operation proved breakable after a lot of hard work (British mathematician Alan Turing was a very important figure behind that effort). Because Germany’s movements became predictable, that work helped turn the tide of the war and sped up the Allies’ victory.
A Watershed Invention: Asymmetric Key Encryption
All of these inventions involved a concept called symmetric key encryption, which relies on shared secrets to crack open information – meaning anyone looking to access the private information has to use the same key.
In the 1970s cryptologists Whitfield Diffie and Martin Hellman invented a landmark encryption tool – asymmetric key encryption. It’s the concept that both HTTPS (the popular protocol used to access a secure web server) and our company, Token, rely on to keep your information private.
The principles behind it are genius. Instead of having a shared key that codes and decodes information, the key for encrypting the information is different from the key that decrypts it –meaning there is no longer a shared, secret key. With asymmetric key encryption, in order to share a secret message, you no longer even have to know the person to whom you are sending it. Most important, for people like us who care deeply about safe authentication and identity protection, the private key itself is never communicated at all, and that means no more shared secrets.
While the Diffie-Hellman protocol has been widely applied, at Token we believe its principles haven’t been fully listened to. Across the globe, we are still using shared secrets to authenticate our identity when we type in passwords (read more about why shared secrets are so bad here). And in the U.S., we’ve only begun a major move to chip-enabled credit cards in the past few years (though the first version was introduced in Europe in 1994). We’re working to apply the lessons of history to today’s advanced technology (like miniaturization and decentralization). To learn more about what we do, visit tokenize.com.
About the Author
Melanie Shapiro is co-founder and CEO of Token, a biometric identity ring that gives users a simple and secure replacement for keys, cards, and passwords. Prior to her time at Token, Melanie co-founded Digsby, a messaging platform for managing online social identities, which was acquired in 2011. She has a BFA in design from the Rochester Institute of Technology and a Ph.D. in consumer behavior; her thesis focused on her work studying community engagement behavior at Microsoft. Melanie is passionate about building an experience layer for cryptography that enables users to protect and have sovereign control of their identities.