data encryption

Process of disguising information as "ciphertext," or data that will be unintelligible to an unauthorized person.

Decryption is the process of converting ciphertext back into its original format, sometimes called plaintext (see cryptography). Computers encrypt data by applying an algorithm to a block of data. A personal key known only to the message's transmitter and intended receiver is used to control the encryption. Well-designed keys are almost impregnable. A key 16 characters long selected at random from 256 ASCII characters could take far longer than the 15-billion-year age of the universe to decode, assuming the perpetrator attempted 100 million different key combinations per second. Symmetric encryption requires the same key for both encryption and decryption. Asymmetric encryption, or public-key cryptography, requires a pair of keys, one for encryption and one for decryption.

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▪ cryptology

also called  Encryption, or Encipherment, 

      the process of disguising information as “ciphertext,” or data unintelligible to an unauthorized person. Conversely, decryption, or decipherment, is the process of converting ciphertext back into its original format. Manual encryption has been used since Roman times, but the term has become associated with the disguising of information via electronic computers. Encryption is a process basic to cryptology (q.v.).

      Computers encrypt data by applying an algorithm—i.e., a set of procedures or instructions for performing a specified task—to a block of data. A personal encryption key, or name, known only to the transmitter of the message and its intended receiver, is used to control the algorithm's encryption of the data, thus yielding unique ciphertext that can be decrypted only by using the key.

      Since the late 1970s, two types of encryption have emerged. Conventional symmetric encryption requires the same key for both encryption and decryption. A common symmetric encryption system is the Data Encryption Standard (DES), an extremely complex algorithm approved as a standard by the U.S. National Bureau of Standards. Asymmetric encryption, or public-key cryptography, requires a pair of keys; one for encryption and one for decryption. It allows disguised data to be transferred between allied parties at different locations without also having to transfer the (not encrypted) key. A common asymmetric encryption standard is the RSA (Rivest-Shamir-Adleman) algorithm.

      Encryption keys selected at random and of sufficient length are considered almost impregnable. A key 10 characters long selected from the 256 available ASCII characters could take roughly 40 billion centuries to decode, assuming that the perpetrator was attempting 10,000 different keys per second.

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