Glossary - D

DATABASE
Information maintained in a computer storage system.

DATA ENCRYPTION STANDARD (DES)
a US government standard (FIPS 46-1) describing a cryptographic algorithm to be used in a symmetric cryptographic application.

DATE/TIME STAMP
the date and time a transaction or document is initiated or submitted to a computer system, or the time at which a transaction is logged or archived. Often it is important that the stamp be certified by some authority to establish legal or other special status. Such a service can be provided by a cryptographic procedure.

DECRYPTION
the cryptographic procedure of transforming ciphertext into the original message cleartext.

DENIAL OF SERVICE
reducing the availability of an object below the level needed to support critical processing or communication, as can happen, for example, in a system crash.

DIGEST
a much condensed version of a message produced by processing the message by a hash algorithm. Commonly, the digest has a fixed length and is not dependent on the length of the original message.

DIGITALISATION
The process of converting information in analogue form into digital form.

DIGITAL SIGNATURE
a digitised analogy of a written signature, produced by a cryptographic procedure acting (commonly) on a digest of the message to be signed.

DIGITAL SIGNATURE STANDARD (DSS)
a US government standard (FIPS 186) describing a cryptographic algorithm for producing a digital signature.

DIGITAL CERTIFICATE
an electronic device which is issued by a third party to attest to the authenticity of the issuer of a document. The combination of encryption techniques and the use of an independent third party prevents fraudulent documents from being accepted as genuine facilities secure transactions between, for example, a government agency and citizens using its services or a bank and its costumers.

DIGITAL SIGNATURE
encryption process that validates the identity of a signer and ensures that a message has not been altered. It is not a digitised version of a handwritten signature. Digital signatures employ public key cryptography along with digital certificates.

DIRECTORY SERVICE
A guide showing how to contact individuals or sections within an organisation via e-mail or the Web.

DISCLOSURE (of data)
The act of making available; the instance of revealing

DOMAIN
A domain is part of the naming hierarchy of the internet. A domain name precisely locates an organisation or other entity on the internet, for instance: http://europa.eu/. An address of the form http://ec.europa.eu/ is a sub-domain.

DOWNLOAD
Transfer of data from a server to your computer's hard disk. You can use your browser or an FTP program to download files to your computer.