Information Security Glossary

Data Encryption Standard (DES)

A widely-used symmetric data encryption algorithm. Like other symmetric data
encryption algorithms, both the sender and the receiver must know and use
the same secret key.

It was developed by IBM 1977 in co-operation with the American National Security Agency . Because it used to be so difficult to break, with 72,000,000,000,000,000 possible key variations, it was banned from export from the USA.

Decryption

The process of decoding data that has been encrypted into a secret format. Decryption requires a secret key or password.

Dictionary Attack

An attack that tries all of the phrases or words in a dictionary, trying to crack a password or key. A dictionary attack uses a predefined list of words compared to a brute force attack that tries all possible combinations.

Encryption

Cryptographic transformation of data (called "plaintext") into a form (called "cipher text") that conceals the data's original meaning to prevent it from being known or used.

Escrow key

Key escrow is an arrangement in which the keys needed to decrypt encrypted data are held in escrow by a third party, so that someone else can obtain them to decrypt messages. Under normal circumstances, the key is not released to someone other than the sender or receiver without proper authorization. Key escrow systems can be considered a security risk as the user puts access to encrypted information into the hands of the escrow agent holding the cryptographic key.

Federal Information Processing Standards (FIPS)

Federal Information Processing Standards (FIPS) are publicly announced standards developed by the United States Federal government for use by all non-military government agencies and by government contractors. Some FIPS standards were originally developed by the U.S. government. For instance, standards for encoding data (e.g. country codes), but more significantly some encryption standards, such as the Data Encryption Standard (FIPS 46) and the Advanced Encryption Standard (FIPS 197).

Hash Function

An algorithm that computes a value based on a data object thereby mapping the data object to a smaller data object. Hash functions are used to generate a one way "check sum" for a larger text, which is not trivially reversed. The result of this hash function can be used to validate if a larger file has been altered, without having to compare the larger files to each other. Frequently used hash functions are MD5, SHA1, SHA-256, 384, 512.