AskDefine | Define encryption

Dictionary Definition

encryption n : the activity of converting from plain text into code [syn: encoding]

User Contributed Dictionary



  1. In cryptography, encryption is the process of obscuring information to make it unreadable without special knowledge, key files, and/or passwords.


process of obscuring information to make it unreadable without special knowledge, key files, and/or passwords

Extensive Definition

In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as ciphertext). In many contexts, the word encryption also implicitly refers to the reverse process, decryption (e.g. “software for encryption” can typically also perform decryption), to make the encrypted information readable again (i.e. to make it unencrypted).
Encryption has long been used by militaries and governments to facilitate secret communication. Encryption is now used in protecting information within many kinds of civilian systems, such as computers, networks (e.g. the Internet e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines. Encryption is also used in digital rights management to prevent unauthorized use or reproduction of copyrighted material and in software also to protect against reverse engineering (see also copy protection).
Encryption, by itself, can protect the confidentiality of messages, but other techniques are still needed to protect the integrity and authenticity of a message; for example, verification of a message authentication code (MAC) or a digital signature. Standards and cryptographic software and hardware to perform encryption are widely available, but successfully using encryption to ensure security may be a challenging problem. A single slip-up in system design or execution can allow successful attacks. Sometimes an adversary can obtain unencrypted information without directly undoing the encryption. See, e.g., traffic analysis, TEMPEST, or Trojan horse.


This term is somewhat a misnomer, but is very commonly used as described above. More correctly, the term "encyphering" should be used (along with "decyphering" for decoding a cryptographically encoded message, when you know the cipher and key). "Decrypt" actually means to decode a message when you do not know the cypher and/or key (i.e., codebreaking), and "encrypt" is meaningless, strictly speaking. However, the common usage is so pervasive even in academic literature, that these distinctions are now generally lost.
The terms "encrypt" and "decrypt" are discouraged in international documents, since they tend to be mistranslated to "inter" (bury) and "disinter".


  • Helen Fouché Gaines, “Cryptanalysis”, 1939, Dover. ISBN 0-486-20097-3
  • David Kahn, The Codebreakers - The Story of Secret Writing (ISBN 0-684-83130-9) (1967)
  • Abraham Sinkov, Elementary Cryptanalysis: A Mathematical Approach, Mathematical Association of America, 1966. ISBN 0-88385-622-0

See also

  • Cryptography - term which encompasses encryption and other concepts used for hiding information
  • Encryption software
  • Cipher - algorithm used for encryption
  • Key - special knowledge needed for successful decryption
encryption in Arabic: تشفير
encryption in Bosnian: Enkripcija
encryption in Danish: Kryptering
encryption in German: Verschlüsselung
encryption in Estonian: Šifreerimine
encryption in Spanish: Criptografía
encryption in Esperanto: Ĉifrado
encryption in French: Chiffrement
encryption in Indonesian: Enkripsi
encryption in Icelandic: Dulkóðun
encryption in Malay (macrolanguage): Penyulitan
encryption in Dutch: Encryptie
encryption in Japanese: 暗号
encryption in Polish: Szyfr
encryption in Russian: Шифрование
encryption in Simple English: Encryption
encryption in Swedish: Kryptering
encryption in Thai: การเข้ารหัส
encryption in Vietnamese: Mã hóa
encryption in Ukrainian: Дешифрування
encryption in Chinese: 加密
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