In the history of cryptography, the Enigma machine was a portable cipher machine used to encrypt and decrypt secret messages. More precisely, Enigma was a family of related electro-mechanical rotor machines — there are a variety of different models. The Enigma was used commercially from the early 1920s on, and was also adopted by military and governmental services of a number of nations — most famously, by Nazi Germany before and during World War II. The German military model, the Wehrmacht Enigma, is the version most commonly discussed. Allied codebreakers were, in many cases, able to decrypt messages protected by the machine (see cryptanalysis of the Enigma). The intelligence gained through this source — codenamed ULTRA — was a significant aid to the Allied war effort. Some historians have suggested that the end of the European war was hastened by up to a year or more because of the decryption of German ciphers.

Read the rest of this article: http://en.wikipedia.org/wiki/Enigma_machine

Today's selected anniversaries:

54 Claudius I was fatally poisoned by his wife Agrippina the younger, making her 17-year old son Nero the next Roman Emperor. (http://en.wikipedia.org/wiki/Nero)

1307 Grand Master Jacques de Molay and thousands of members of the Knights Templar, a monastic military order, were simultaneously arrested by agents of Phillip the Fair and subsequently tortured into "admitting" heresy. From that Friday on, Friday the 13th was considered by followers of the Templars as an evil and unlucky day. (http://en.wikipedia.org/wiki/Knights_Templar)

1843 The Independent Order of B'nai B'rith, the oldest continually-operating Jewish service organization in the world, was founded in New York City. (http://en.wikipedia.org/wiki/B%27nai_B%27rith)

1845 Voters in the Republic of Texas approved a proposed constitution, that if accepted by the United States Congress, would make Texas a U.S. state. (http://en.wikipedia.org/wiki/Republic_of_Texas)

1943 World War II: With a new government led by General Pietro Badoglio, parts of Italy switched sides to the Allies and declared war on Germany and Japan as well as Northern Italy. (http://en.wikipedia.org/wiki/Pietro_Badoglio)

Wikiquote of the day:

"So many of our dreams at first seem impossible, then they seem improbable, and then, when we summon the will, they soon become inevitable." ~ Christopher Reeve (http://en.wikiquote.org/wiki/Christopher_Reeve)