3DES: An algorithm that is based on DES (data encryption standard) for symmetric deciphering of data. Compared to DES, the 3DES algorithm is considered as more secure according to today’s standards. The 3DES has a key length of 168 bits, however, the effective key length is 112 bits due to the assigned procedure.


AAA: Authentication, Authorization, Account


Asymmetrical encrypting: Compared to the symmetrical encrypting the asymmetrical method implies the using of different keys for the encryption and for decryption. For encryption and verification of digital signatures the public key is used, for decryption and signing the secret key is used.


Audit: Examination of existing systems and implementations


BIND (Berkeley Internet Name Daemon): Service, which allows the conversion of names of the DNS to IP addresses (and vice versa).


BSD (Berkeley Software Distribution): UNIX package of the University of Berkeley. Primarily this package was sold, later on it was divided into several free variants (FreeBSD, NetBSD, OpenBSD) with their own license, which allowed the reprivatization.


Backdoor: A way of getting into a password-protected system without using the password. It is usually a carefully guarded secret to prevent abuse and misuse.


Blowfish: A symmetrical encrypting algorithm that was developed by Bruce Schneier. It is free available and has a key length of 128 bits.


Brute Force Attack: It is an attack on encoded data and means hurling passwords at a system until it cracks.


CA (Certification Authority): Certification instance within a hierarchical certification model.


CAST5: Symmetrical encrypting algorithm with 128 bits key length.


CERT (Computer Emergency Response Team): Emergency team which helps you in case of an attack or virus.


Character set encrypting: This is a method to convert characters into numbers.


Client: Clients are devices that use the provided services of a server.


dDoS (Distributed Denial of Service): This is a version of the DoS attack that spread around.


DES (Digital Encryption Standard): This term refers to a block cipher algorithm for encrypting data designed by the National Bureau of Standards with a key length of 56 bits. The DES-algorithm is considered as quite insecure according to today’s standards and should not be used.


Dictionary attack: The attacker uses a huge list of words mainly from a dictionary in order to discover passwords.


DNS (Domain Name System): The definition of a hierarchical name system for internet domains.


DSA (Digital Signature Algorithm): A very secure algorithm for the signature of messages that was developed by the NSA.


DoS (Denial of Service): This attack implies the occupation of system resources in such a way that services are no longer available.


Domain: Area within a hierarchical name system on the internet, such as DN-systems.de.


email (electronic mail): Electronic mail on the internet.


ElGamal: An algorithm which can be used for the asymmetrical encryption and signing of messages.


Embedded Systems: Small entire computer system that does not look like this.


Entropy: This term comes from the field of thermodynamics and is a measure for the disorder of a system.


Ethernet: Transport protocol for LANs (Local Area Network).


Eventlog: Method of recording events used by systems of Microsoft.


Exploit: This term refers to the exploiting of security holes.


FSF (Free Software Foundation): This organization was founded by Richard Stallman ? among others – in 1985 with intention of supporting GNU projects in developing of free software.


FTP (File Transfer Protocol): FTP allows the copying of internet files.


Firewall: Hard and/or software that controls the data flow between a private and an unprotected network (LAN, Internet).


Forensic analysis of a work station: Forensic examination of a work station after an attack.


Forensic Server Analysis: Forensic examination of a server after an attack.


GNU GPL (GNU general Public License, abbreviated to GPL): GNU GPL is the most well-known and extensive free software license. The GPL permits the usage, change and distribution of software and forbids the exclusion of usage software, such as reprivatization of software that was derived from them.


GNU : (recursive name for GNU Is emergency Unix) project of the FSF for the creation of a free operating system. The GNU Tools is part of the free operating system GNU/Linux.


Gateway : Transition between two nets or two stages of safety


HPUX: UNIX variant of the company Hewlett-Packard


HTTP (Hypertext Transfer Protocol): The protocol is used for moving documents such as websites around the internet.


Host: computer or participant in a net that can be identified by its IP address.


Housing: This term refers to locating of servers. Due to this you do not need a user-to-user-connection.


IDEA (Internationally Data Encryption Standard): IDEA is an algorithm for the symmetrical encryption of data.


IDS (Intrusion Detection System): IDS is a system that is used for the electronic intrusion detection with computer systems or nets.


IETF (Internet Engineering Task Force): The IETF is an informal organization for the specification of Internet Standards. Most important documents are the RFCs (see also RFCs!)


IMAP (Internet Message ACCESS Protocol): A protocol which permits the administration of emails on a server.


IOS (Internetworking operating system): This term refers to a operating system of the Company Cisco Systems


IP (Internet Protocol): Together with TCP, UDP and ICMP they are the basis protocols of internet communication.


IPv4 (Internet Protocol Version 4): This is an unambiguous numerical term consisting of four bits that refers clearly to one machine on the internet.


IPv6 : IPv6 is an unambiguous numerical term of the next computer generation that refers to one machine on the internet


IRIX (I R I X): UNIX operating system of the enterprise Silicon Graphics


Illegal data: Data whose possession is not allowed according to the law of the Federal Republic of Germany.


Interior offender:
Intruder who attacks the company’s network from the inside or works for the attacked company.


Internet Worm: This software program caused a major part of the internet network to crash by replicating and generating spurious data. It spreads via the Internet and is able to cause serious damage on computers. The “I-LOVE-YOU”-worm is current example.


cernel: This is a central component of the modular Unix operating system which administers the memory, organizes processes and makes essential operations available.


LAN (Local AREA Network): This term refers to a net whose implementation is spatially limited.


Log file: File that tracks access activity for a host resource.


MD5 (Message Digest version 5): A very secure encrypted hash algorithm.


MIME (Multi-PUR-Float Internet Mail Extensions): A standard for the transmission of any data by email).


MTA (Mail Transport Agent, Mail Server): A program that transmits email within networks (such as an intranet of a company).


MUA (Mail User Agent, Mail Client, E-Mail Program): A program which allows the users to read and write emails.


Mailbox : Storage place of the emails


Mail domain: This term refers to the whole sphere of the emails / The domain is stored in a mailbox.


Mail server: (see MTA)


Malware: Generic term for malicious software


Man-in-the-Middle Attack: This term refers to an attack that is carried out by an intruder who is located between two communication parties and counterfeits data.


NTP (Network Time Protocol): A protocol to maintain a common sense of ‘time’ among Internet hosts.


Name server: A server that provides the data for the domain on the internet.


NetBSD: This term refers to free BSD Unix version that is focused on portability.


One-way Hash: This term refers to not reversible hashing. (see also hashing)


Open Source: A common used marketing term for free software that was introduced by the Open SOURCE Initiative. This initiative was found by Eric Raymond and Bruce Perens in 1997.


OpenBSD: A free BSD Unix version that is focused on security.


POP3 (Post Office Protocol): A protocol for the retrieval of emails from a mail server.


Pattern generator: A forensic tool to generate search pattern or to adapt to the encoding.


Protocol: An agreement over syntax and semantics of electronic communication.


RFCs (Request for comments): These documents are used to specify open internet standards and are in general discussed in meetings of the IETF (see IETF).


RootKits: A modular concept that allows an intruder to stay in a system without being noticed by the administrator.


SHA1 (Secure Hash Algorithm One): A hash algorithm with a key length of 160 bits that was developed by the NSA.


SMTP Relay: A system which is used for sending via SMTP.


SMTP (Simple Mail Transfer Protocol RFC2822): Protocol that specifies the sending of emails.


SNMP (Simple Network Management Protocol): Protocol for the administration of network devices.


Spam: Slang word for unwanted email which have no relevance.


SSL (Secure Socket Layer): This is an encryption procedure on socket basis


Security holes: Error that leads to security problems that could be exploited by intruders.


Weak point scan:
A scan for security problems in a system


Security administration: Administration of all security-relevant components, such as IDS, firewalls and virus protection


Server: Computer that provides services which could be used by clients.


Sniffing: This term refers to the monitoring of data during a network transmission.


Solaris: UNIX operating system developed by SUN Microsystems


Syslog: Method of event information logging wih UNIX/Linux systems.


TCP (Transmission Control Protocol): Apart from IP, UDP and ICMP one of the basic internet protocols.


TLS (Transport Layer Security): A version of SSL


Telnet: Protocol that allows the remote control of a computer via internet.


Timekeeping: A method to keep the exact time on the system.


Tunnel: Connecting two communication partners via a point-to-point connection.


Twofish: A symmetrical encrypting algorithm with alternatively 128 or 256 bits key length, developed by Bruce Schneier.


UNIX: UNIX is a multitasking and multi-user operating system. The name is derived from the forerunner system MULTICS (Multiplexed Information and Computing service). It was focused on simplicity and there therefore UNICS (Uniplexed Information and Computing service). UNICS was renamed to UNIX.


VPN (Virtual Private Network): This is a network which is used to route another network.


Virtual Server: This term refers to many systems that are based on one hardware only.


WLAN (Wireless Local Area Network): This is a network that is based on radio technology and works without wires to connect hosts.


WWW (World Wide Web): The term WWW refers to a world-wide net that is based on HTTP.


Web Server: This is a server that provides websites via HTTP protocol.