Encryption History Draft (New)
Intro/Roots of Encryption
As people around the world become more and more dependent on sending important information through unsecure channels, the need for encryption is higher than ever. However, uses of encryption techniques date back over 4000 years. The earliest recording of such encryption use occurred in Egypt where hieroglyphic inscriptions on the tombs of noblemen were written with a number of unusual symbols to obscure the meaning of the inscriptions. In 5 BC, the Spartans developed a cryptographic device called a Scytale. The Scytale was a cylinder in the possession of both the sender and receiver around which a message could be wound to perform a transposition, changing the ordering of the letters. In 50 BC, Julius Caesar used a substitution cipher to send secret messages where each letter was replaced by a different letter a certain distance ahead or behind the actual letter in the alphabet. Although the roots of cryptography can be traced back thousands of years, cryptography did not garner much attention until around the time of World War I.
WWI
During World War I, a few key events forced the Germans to send messages across easily interceptable channels, making encryption a necessity. Early on in the war, many of Germany’s telegraphy lines in France, Belgium and crossing the Atlantic Ocean were cut. Also, following the advent of wireless telegraphy in the early 20th century, radio communication was the only way to immediately communicate with vessels at sea and armies on the move. For these reasons, the Germans had to rely highly on wireless communication or communication using Swedish and American cables that were routed through Britain. The British Admiralty's intelligence service took advantage of this access to German information by intercepting many messages. The result was a cryptanalysis organization know as the Room 40 group, named after the location of their operation in the Old Admiralty Building. The Room 40 group was highly successful in breaking German ciphers and codes to decrypt many messages about German naval activity. The decryption efforts were also aided by the discovery of cipher books, found on the body of a German soldier after the wreck of the light crusier Magdenburg, given to Britain by the Russians. Shipwright E.C. Miller also made several deep dives to rescue books from sunken U-boats containing important German codes.
The most notable decrypted message by the Room 40 group is known as the Zimmerman telegram. In January of 1917, British code-breakers William Montgomery and Nigel de Gray were given an encrypted telegram sent over Swedish and American lines and intercepted in Britain. The Room 40 group already knew the cipher and was able to quickly decrypt much of the message. The message was sent by the German foreign minister to Mexico declaring a start to unrestricted submarine warfare and urging Mexico to help attack the US and encourage Japan to do the same. The British knew the significance of the message and the need to pass it on to the Americans. To protect the source of the interception, a message was intercepted on the Mexican side and decrypted. This version was released to the press a month later, deceiving the Germans into thinking that it was obtained via espionage in Mexico. The message ultimately prompted President Woodrow Wilson to declare war on Germany in April of 1917.
WWII
The importance of encryption continued in the time following World War I and into World War II. The British again played a major role, this time their encryption efforts were codenamed Ultra. The Ultra project attempted to decrypt radio traffic and Enigma messages. Enigma was a German encryption machine, which was thought to be unbreakable in the 1920s. The Enigma was a portable machine that consisted of a keyboard, rotating disk, and a lamp. These rotors contained each of the 26 letters of the alphabet and would rotate with each key press. The output letter produced when a letter was typed on the Enigma keyboard was a product of the positioning of these rotors. Depending on how the rotors lined up, the lamp would light a different letter. There were many different types of the Enigma machine with varying numbers of rotors and even commercial versions.
There were many factors contributing to the success of Ultra in breaking the Enigma encryption. The Ultra team, which included computer science pioneers Alan Turing and Max Newman, received help in 1939 when they learned that the Polish had made fundamental breaks into Enigma dating back to 1932. Copies of Enigma manuals obtained from a disgruntled German soldier were essential to the Polish efforts. The Poles were able to obtain to obtain “day keys” to decrypt Enigma messages for a day. One critical weakness of Enigma proved to be that it would never output the same letter that was keyed. This was helpful because often an operator would simply send a test message by repeatedly typing the same letter and the encrypted message would not contain that keyed letter. This flaw was also helpful in applying cribs, clues to decrypt known messages like “Dear Sir” or “Hail Hitler.” Although the Germans did modify the Enigma machines a few times by adding additional routers, by 1945 nearly all German Enigma traffic could be translated in a day or two. The Germans still remained confident of its security and continued to transmit Enigma messages. This alerted the allied forces to the locations of the German army and navy and led to various surprise attacks that the Germans could not explain.
Also during World War II, the Americans were working on breaking the Japanese encryption as well. In 1943, the US intercepted important Japanese messages sent using a cipher called JN-25. The code turned out to be a subset of US Army code used in the Spanish-American war of 1898, but the Japanese did not know the US knew how to break it. Intercepted messages informed the US Army Air Corps of the plane that Admiral Yamamoto Isoroku would be in for a tour of the South Pacific. This information directly led to his assassination. Also of note was the US effort to break the encryption scheme of the Japanese Purple machine. This work, codenamed Magic, was helped by Japanese misuses in the technique. The Purple machine was an excellent form of encryption, but often, operational errors like poor key choices compromised its security and led to the US Signals Intelligence Service ultimately breaking the code.
Cold War
Starting in the 1940s and continuing through the Cold War, the US and Britain also collaborated to break Soviet encrypted messages. Codenamed the Venona project, out of hundreds of thousands of messages, thousands were able to be decrypted. The Soviets were once thought to be using unbreakable one time pads, but reuse of the pads led to flaws in their system. The decryptions were a product of espionage and also the error of reusing pads. The majority of messages were KGB communications and were used to gain information about Soviet behavior. Also, the existence and in some cases, identification of US, Canadian, British, and Australian spies was discovered. The existence and the significance of the Venona project was not made publc until 1995.
Current Stuff
Up until the last 40 years, it was believed that cryptography would be more secure if more information about it was kept secret. As history showed that keeping a cipher secret could not guarantee complete information security, there was a shift toward publicly known standards with only secret keys. In 1976, an encryption scheme called DES (Data Encryption Standard) was adopted as the Federal Information Processing Standard (FIPS) for use by for use by all non-military government agencies and government contractors. DES was highly scrutinized and has since been proved to be unsecure, mostly because of its small 56-bit key size. Although DES had its shortcomings, its standardization sparked much research and advancement of the cryptography field. The interest in the subject became more of a public concern, rather than solely a military one. Also in the late 1970’s, public key cryptography, where both the sender and receiver had their own private keys and shared a known public key, was developed as an alternative to the private key cryptography that was used in the past. The most notable public key encryption scheme is called RSA. Also, there is currently a great deal of work towards advancing encryption techniques. A new topic is quantum cryptography, where it is possible to securely pass keys because the keys cannot be intercepted without being changed. It is clear that the great need for cryptography in today’s society will continue to drive the field forward.
Today, a large number of people communicate over insecure channels like the Internet, e-mail, and other wireless devices, making encryption more necessary than ever. Uses of encryption are clearly visible in everyday applications. ATMs are now mandated to use Triple DES (an improved DES scheme where three DES encryptions are performed). RSA has become highly used to encrypt data sent over the Internet and is used in web browsers like Netscape Navigator and Microsoft Internet Explorer. E-mail uses an encryption called PGP (Pretty Good Policy) to provide cryptographic privacy and authentication. With information transfer becoming a critical aspect of modern society, encryption has also become increasingly important. The average person wants to send secure e-mails. Banks want to ensure security for their online banking customers. The government wants to monitor terrorist communication over the Internet. In all of these situations, some type of encryption is critical to ensuring that the informatinon is properly protected. The various encryption schemes and their effectiveness is currently of great interest to many people.
