Extra data appended to a message which identifies and authenticates the sender and message data using public-key cryptography. Driver-level encryption means that the user has a logical drive that has all data on it encrypted. This is how PC Guardian's Encryption Plus Hard Disk product works. The rules under which the export of cryptographic software from the US is governed. See also cryptography .
Some cryptographic algorithms rely on the difficulty of factoring large numbers.
File-level encryption means that every file is encrypted separately. This is how PC Guardian's Encryption Plus Folders product works. A European standard for encrypting the links between digital mobile telephones and base stations. See one-way hash function . I IDEA See International Data Encryption Algorithm .