a) The decoding of the Zimmerman Telegraph was a principal factor in getting the US to enter World War I in 1917. The telegraph was sent from Arthur Zimmerman, a German foreign secretary, to a German ambassador in Mexico. In the coded message (see image), a proposal was made that Mexico declare war against the US in exchange for financial benefits and lost territory. The British then intercepted the message, eventually decoding and providing its contents to President Woodrow Wilson. Check out the decoded Zimmerman Telegraph next. b) In 1977, Ronald L. Rivest, Adi Shamir and Leonard M. Adleman published details of their RSA algorithm and the patent was issued in 1983. It became the key security technology that would make eCommerce possible. c) DES was the de-facto encryption algorithm for the US government for over 25 years. The encryption algorithm was adopted by the US government (NIST) in 1977 (as FIPS PUB 46). The algorithm was submitted by IBM and is attributed to the work of Horst Feistel. d) One of the best-known electro-mechanical encryption machines is the German Enigma. It was heavily used in WW II, as the Germans improved on the weakness of poor message secrecy in the WWI Zimmerman incident. The machine has 3x10114 possible combinations. The US Navy captured the Enigma machine and several codebooks on the German U-505 submarine in 1944, which lead to the intelligence that helped end the war early. e) In Greek, Stegonos means “concealed”, and graphei means “writing” in Greek. This concealed writing, can be as simple as hiding text underneath another object, but in today’s technology this could mean hiding information within encrypted data. OpenStego is an Open Source application that lets you hide images within other files and will encrypt the results for you. f) The US Marine Corps enlisted Navajo Indians to help transmit sensitive messages over telephone and radio during WWII. Using the Navajo dialect, in addition to specific coding, was faster than using machines to encrypt and decrypt messages. The use of Indian dialects started as early as the first World War (Choctaw code talkers) and continued through the Korean War. g) Cryptography has the makings of one of the best drama and action movies of all time. There are lies, deception, secrets exchanged, codes broken, wars being fought, and millions of lives at risk in the balance. The history of cryptography dates back several thousands of years, possibly some of which we may never uncover. From the Caesar cipher, to the Enigma of WWII, to modern cryptography of RSA, much of world history is made by which secrets are known by whom and when. h) The decoded Zimmerman Telegraph, sent by Arthur Zimmerman (a German foreign secretary) to a German ambassador in Mexico. The message, which proposed Mexico declare war against the US in exchange for financial benefits and lost territory, was a principal factor in getting the US to enter World War I (see previous picture for coded message that was intercepted by the British). i) Invented by Blaise de Vigenère, the cipher is a more complex form of the Caesar cipher; in this case by using multiple alphabets. To encrypt a message, you need a keyword and a set of alphabets (a matrix). To encrypt you take the first letter of the keyword and find it in the column, and the first letter of plaintext and match it with the associated row. For example, the first letter of the keyword is P and plaintext is C; the encrypted text is R. j) US army mechanism for encryption based on the principles pioneered in the Thomas Jefferson's Cipher Wheel (see previous page). Like the Jefferson Disk, the M-94 has has a random set of letters, with the actual key to encryption being the arrangement of 36 disks. k) Syctale is Greek for baton. Using a cylinder of different diameter sizes, one can encrypt and decrypt using what is now referred to as transposition cipher. Letters are arranged in different sequence depending on the diameter size. This system can be broken by trying to read the message using batons (cylinders) of different sizes. l) A one-time pad (OTP) is an algorithm where a message is combined with a key equivalent to the size of the message. The key must be completely random and only used once. m) Philip Zimmerman is the man that created Pretty Good Privacy (PGP) in 1991. The e-mailencryption tool was released to newsgroups and the Internet, but the release of the popular encryption program would later land Zimmerman in hot water with the US government as exporting cryptography over 40 bits was against US export regulations at that time. n) Cryptographic Hashes are needed for computing Digital Signatures, which in turn are needed for certificates that power eCommerce. NIST has a series of approved cryptographic hashes referred to as Secure Hash Algorithm (also known as Message Digests). A hash is taking a large block of data of any size and converting it to a fixed size string, usually between 128 and 512 bits (depending on the algorithm). o) Named after Julius Caesar— the Roman General who commonly used the cipher—The Caesar cipher is one of the best known (and most easily broken) substitution ciphers. It is known as a substitution cipher because letters are substituted for one another (commonly referred to as an offset or shift). In the example here, A is substituted for D, B for E, and so forth; the shift is 3. The key in this case is the size of the alphabet. It’s easy to break this cipher by trying all the substitutions. p) Jefferson invented a wheel-based cryptosystem in the late 1790s. His invention would later surface as the US army mechanism for encryption over 150 years later, called the M-94 (see next page). Each wheel has a random set of letters. The key was actually the arrangement of the 36 disks, which has a complexity of n factorial, very secure for the time (36! = 3.7x1041).