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evolution-of-encryption

Encryption has evolved significantly since the first signs of it in 1900 BCE. The one unifying trend? The need to keep secrets, as can be seen in how encryption has evolved over the years.

If we go back in time, it is clear that encryption was not born of the need to compute like we see today, but as a means of securing messages and/or secrets for even the most ancient of civilizations. From changing hieroglyphics to manual encryption machines, to our now digital landscape, encryption continues to evolve. When I first began this project, which required that I research the history of data encryption, one trend remained the same: what always seemed to prompt sudden development…was driven by the need to keep secrets during turbulent times.

Here are 3 primary examples of how war drove developments in secret protection and encryption.[1]

The American Revolution: Almost an Encryption Revolution
Encryption innovation extends far back into the 1790s, around the time of the American Revolution. While serving as the secretary of state for the first U.S. President, George Washington, U.S. Founding Father Thomas Jefferson created a “wheel cypher” for encrypting military communications. Among these were letters between he and Meriwether Lewis – the President’s personal secretary – and his review of US Army officers in a bid to ferret out potential traitors to the Loyalists.[2] Before this, Jefferson had relied on messengers to hand-carry sensitive letters; this was not secure enough once he became the U.S. Minister to France, at a time when European postmasters routinely read all diplomatic correspondence.

Jefferson’s cypher system used a set of wheels, each with 26 letters of the alphabet in a random order. Jefferson only used the device briefly, if at all; sources indicate the idea was abandoned by 1802. It was forgotten and only rediscovered in 1922.[3]

WWI and the Rotor Machine

While the Jefferson disk remained hidden away in obscurity, another cryptanalyst was independently working on a similar machine: Étienne Bazeries. Bazeries invented his “Bazeries Cylinder” in the 1890s, as part of his work improving the official French military transposition system, which he claimed “offer[ed] little resistance to solution.”[4] He later assisted in solving German military ciphers during the First World War.[5]

Across the pond, in 1917, Major Joseph Mauborgne used both the Jefferson wheel and the Bazeries cylinder as reference points for a new machine for the US Army to encrypt and decrypt messages during the war. This machine – the M-94 decoder – was one of the first rotor machines, or mechanized encryption devices to be used in modern cryptology – and modern warfare.

Center Stage: WWII

 

Cryptography ultimately had a profound effect on the outcome of World War II, in a variety of fronts and situations.

Let’s begin with the Axis powers. The Germans used an enigma machine to create codes for military communication – a sophisticated rotor machine invented by engineer Arthur Scherbius in 1918 and marketed in 1923.[6] Versions of the Enigma machine were also used by the Japanese and Italian armed forces as well.

Early in the war, the Allied forces were able to decrypt some of the German coded messages, thanks to the works of Polish cryptanalysts colluding with a German defector in the 1930s. They later passed this information on to Britain and France.[7] Throughout the war, highly classified Allied teams worked on cracking German and Japanese codes, using the knowledge they had gained from the Polish research and over time; this knowledge came to a head during the Battle of Midway.

In 1942, a team of cryptanalysts working for the United States Navy made a breakthrough in cracking JN-25, the code used by Japanese Navy forces for important operational transmissions. JN-25 consisted of 45,000 five-digit numbers, with each number representing a word or phrase; each message was also “super-enciphered” using an additive table. Commander Joseph Rochefort and his team managed to make enough progress on the code to decipher Japanese plans for a surprise attack on Midway, and to anticipate the battle enough to prepare forces for the June 4, 1942 attack. Ultimately, US forces sank all 4 Japanese carriers facilitating the attack, rendering them useless.[8]

Ultimately, the German Enigma machine not only helped birth modern cryptography; it helped birth modern computing. Alan Turing was among a team of British codebreakers focusing on the Enigma machine decryption project from 1938 onward. As part of this project, he designed a machine called the Bombe, which aided the cryptanalysts by automatically searching through possible permutations of advanced Enigma machines for applicable messages. By the end of the war, British forces were able to read all German Naval Enigma traffic – arguably one of the first practical applications of a machine using mathematics to complete complex operations, the very principle of modern computing itself.[9]

Modern Encryption

As we have seen, historically, times of great conflict have been major catalysts for innovation in encryption and cryptography. This is due to the fact that the need to communicate secretly is crucial in wartime. This same need once again arose in the early stages of the computing and digital era. In 1976, Diffie and Hellman published a paper called “New Directions in Cryptography.”

Quoting from their paper:

The development of computer-controlled communication networks promises effortless and inexpensive contact between people or computers on opposite sides of the world, replacing most mail and many excursions with telecommunications. For many applications, these contacts must be made secure against both eavesdropping and the injection of illegitimate messages.

Indeed, the digital age ushered in huge innovation in cryptography in the 1980s and 1990s, providing us with strong solutions to protecting data in many different scenarios. However, the past 10-20 years have once again pushed us to new innovation due to the growing attack landscape and to new computing paradigms.

Today, the encryption war is not physical; it’s a war of ideas and information that has embraced our digital world. Encryption is used not only for matters of national defense, but also for financial security, for business security, and for security of intellectual property, among others.

While encryption is used everywhere, the days of private data centers with computers under full control of organizations are long gone. Computing is carried out across private data centers and multiple clouds, employees use their own devices to connect to networks, and computing tasks are outsourced to SaaS providers. We can no longer assume that we can protect what is inside our network, both because our network is no longer a single entity and because attackers are everywhere. As a result, cryptographic solutions need to work in diverse and zero-trust settings, and legacy paradigms for key management and protection need to change.

[1] I will be addressing pure encryption – obscuring messages through symbol replacement and algorithms – but not stenography, or the simple obfuscation of messages.

[2] “Coded Review.” Monticello, Monticello and the Thomas Jefferson Encyclopedia, www.monticello.org/thomas-jefferson/louisiana-lewis-clark/preparing-for-the-expedition/coded-messages/coded-review/.

[3]  Wheel Cipher, Monticello and the Thomas Jefferson Encyclopedia, www.monticello.org/site/research-and-collections/wheel-cipher

[4] Kahn, David, The Codebreakers. 1967, 2d ed. 1996. (ISBN 0-684-83130-9).

[5] Candela. The Military Cipher of Commandant Bazeries, 4-10.

[6] “History of the Enigma.” Enigma History, The Crypto Museum, 14 Mar. 2012, www.cryptomuseum.com/crypto/enigma/hist.htm.

[7] “War of Secrets: Cryptology in WWII.” National Museum of the United States Air Force™, National Museum of the United States Air Force™, 1 May 2015, www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196193/war-of-secrets-cryptology-in-wwii/#:~:text=Cryptology%20is%20the%20study%20of,helped%20shorten%20the%20war%20considerably.

[8] Wheadon, Patrick D. “The Battle of Midway: How Cryptology Enabled the United States to Turn the Tide in the Pacific War.” National Security Agency.

[9] Watson, Ian. “How Alan Turing Invented the Computer Age.” Scientific American Blog Network, Scientific American, 26 Apr. 2012, blogs.scientificamerican.com/guest-blog/how-alan-turing-invented-the-computer-age/.