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Encryption is the conversion of datainto a form, called a ciphertext, that cannot be easilyunderstood by unauthorized people. Decryption is theprocess of converting encrypted data back into its original form,so it can be understood. The use of encryption/decryption is as old as theart of communication. In wartime, a cipher, often incorrectlycalled a "code," can be employed to keep the enemy fromobtaining the contents of transmissions. (Technically, a codeis a means of representing a signal without the intent of keepingit secret; examples are Morse code and ASCII.) Simple ciphersinclude the substitution of letters for numbers, the rotation ofletters in the alphabet, and the "scrambling" of voicesignals by inverting the sideband frequencies. More complexciphers work according to sophisticated computer algorithms thatrearrange the data bits in digital signals. In order to easily recover the contents of anencrypted signal, the correct decryption key isrequired. The key is an algorithm that "undoes" thework of the encryption algorithm. Alternatively, a computer canbe used in an attempt to "break" the cipher. The morecomplex the encryption algorithm, the more difficult it becomesto eavesdrop on the communications without access to the key. Encryption/decryption is especially important in wirelesscommunications. This is because wireless circuits are easier to"tap" than their hard-wired counterparts. Nevertheless,encryption/decryption is a good idea when carrying out any kindof sensitive transaction, such as a credit-card purchase online,or the discussion of a company secret between differentdepartments in the organization. The stronger the cipher -- thatis, the harder it is for unauthorized people to break it -- thebetter, in general. However, as the strength ofencryption/decryption increases, so does the cost. In recent years, a controversy has arisen overso-called strong encryption. This refers to ciphers thatare essentially unbreakable without the decryption keys. Whilemost companies and their customers view it as a means of keepingsecrets and minimizing fraud, some governments view strongencryption as a potential vehicle by which terrorists might evadeauthorities. These governments, including that of the UnitedStates, want to set up a key-escrow arrangement. Thismeans everyone who uses a cipher would be required to provide thegovernment with a copy of the key. Decryption keys would bestored in a supposedly secure place, used only by authorities,and used only if backed up by a court order. Opponents of thisscheme argue that criminals could hack into the key-escrowdatabase and illegally obtain, steal, or alter the keys.Supporters claim that while this is a possibility, implementingthe key escrow scheme would be better than doing nothing toprevent criminals from freely using encryption/decryption.
Last updated on: Jul 10, 2006
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