SnapGear 2.0.1 user manual Appendix B Terminology, Term Meaning

Appendix B – Terminology

This section explains terms that are commonly used in this document.

Term	Meaning
ADSL	Asymmetric Digital Subscriber Line. A technology allowing high-speed
	data transfer over existing telephone lines. ADSL supports data rates
	between 1.5 and 9 Mb/s when receiving data and between 16 and 640
	Kb/s when sending data.
Advanced	The Advanced Encryption Standard is a new block cipher standard to
Encryption	replace DES, developed by NIST, the US National Institute of
Standard (AES)	Standards and Technology. AES ciphers use a 128-bit block and 128,
	192 or 256-bit keys. The larger block size helps resist birthday attacks
	while the large key size prevents brute force attacks.
Aggressive Mode	This Phase 1 keying mode automatically exchanges encryption and
	authentication keys and uses less messages in the exchange when
	compared to Main mode. Aggressive mode is typically used to allow
	parties that are configured with a dynamic IP address and a preshared
	secret to connect or if the CyberGuard SG appliance or the remote
	party is behind a NAT device.
Authentication	Authentication is the technique by which a process verifies that its
	communication partner is who it is supposed to be and not an imposter.
	Authentication confirms that data is sent to the intended recipient and
	assures the recipient that the data originated from the expected sender
	and has not been altered on route.
Automatic	This type of keying automatically exchanges encryption and
Keying, Internet	authentication keys and replaces them periodically.
Key Exchange
(IKE)
Block cipher	A method of encrypting text (to produce ciphertext) in which a
	cryptographic key and algorithm are applied to a block of data (for
	example, 64 contiguous bits) at once as a group rather than to one bit
	at a time. DES, 3DES and AES are all block ciphers.
BOOTP	Bootstrap Protocol. A protocol that allows a network user to
	automatically receive an IP address and have an operating system boot
	without user interaction. BOOTP is the basis for the more advanced
	DHCP.
CA Certificate	A self-signed certification authority (CA) certificate that identifies a CA.
	It is called a CA certificate because it is the certificate for the root CA.

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Appendix B – Terminology