terms Flashcards by Francis Sanmocte

is the transfer of information from one point to another; consist of message, sender, medium, receiver

Data communications

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information that has been processed and organized, it can be alphabetical, numeric, or symbolic information

Data

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single transmission line; one bit is transmitted at one time; long distance communications; (serial-by-bit transmission)

Serial Data Transmission

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transfer data on a parallel link, a separate line is used as a clock signal; data transmission speed is high

Parallel Data Transmission

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involves only two locations or stations.

Two-point configuration

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involves three or more stations or terminals.

Multipoint configuration

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is when signals travel in one direction only.

Simplex

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is when signals travel in both directions, but one at a time

Half duplex

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is a two-way communications and signals travel in both directions simultaneously.

Full duplex

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corrupted data during transmission.

Error

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only one bit is going to be changed.

Bit error

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is a change in two or more bits.

Multiple Bit error

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change in more than 1 consecutive bits.

Burst error

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the process of monitoring the received data and determining when a transmission error occurred.

Error detection

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also known as parity check; it can detect single bit error.

VRC (VERTICAL REDUNDANCY CHECK)

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also called as the two-dimensional parity; the parity bit is appended to every data block whereas in LRC, a block data bit is organized in rows and columns.

LRC (LONGITUDINAL REDUNDANCY CHECK)

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it can detect all errors involving an odd number of bits; it can detect errors involving an even number of bits.

CHECKSUM

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perform binary division operation.

CRC (CYCLIC REDUNDANCY CHECK)

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detects and corrects transmission errors at the receive end without calling for retransmission; bits are added to message prior to transmission.

Forward Error Correction (FEC)

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dependent on the number of bits in the data character.

HAMMING CODE

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metallic circuit formed by two conductors insulated from each other; it uses one line for transmission of electric waves in both directions.

Two - Wire Circuit

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two-way circuit using two paths so arranged that communication currents are transmitted in one direction only on one path, and in the opposite direction on the other path.

Four - Wire Circuit

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Computer, Network Printers, VoIP Phones, Telepresence endpoint, Security Cameras, Mobile handled phones

END NODE DEVICES

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switches, wireless access point, routers, security devices (Firewall), bridges, hubs, repeaters, cell tower

INTERMEDIARY NODES

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ethernet, fiber optic cable, coaxial cable, USB cable

Wired Media

infrared, radio, microwaves, satellite

Wireless Media

email, storage services, file sharing, instant messaging, online game, voice over IP, video telephony, world wide web

Services

physical layout of nodes on a network

Physical topology

consists of a single cable-called a backbone-connecting all nodes on a network without intervening connectivity devices

Bus topology

each node is connected to the two nearest nodes so the entire network forms a circle; one method for passing data on ring networks is token passing

Ring topology

every node on the network is connected through a central device called hub or switch.

Star topology

each computer connects to every other; high level of redundancy.

Mesh Topology

is a combination of Bus and Star topology.

Tree topology

it is a set of rules and configurations designed to protect the integrity, confidentiality and accessibility of computer networks and data.

Network security

protect the data that has been transmitted.

Confidentiality

ensuring that information cannot be modified without detection

Integrity

ensuring information can be accessed when needed

Availability

potential for violation of security; action or event that could breach security and cause harm.

Threat

an assault on system security that derives from an intelligent threat.

Attack

action that compromises the security

Security attack

detect, prevent, or recover from a security attack.

Security mechanism

enhance the security, counter security attacks and provide the service.

Security service

attempts to learn or make use of information from the system

PASSIVE ATTACK

going to understand or know what is the data that is being transmitted between the sender and the receiver

Release of message contents

going to observe the pattern of messages from sender and the receiver.

Traffic analysis

involve some modification of the data stream or the creation of a false stream.

ACTIVE ATTACK

is an attack that uses a fake identity

Masquerade

detects a data transmission and fraudulently has it delayed or repeated.

Replay

attack on the integrity of the original data.

Modification of messages

attack meant to shut down a machine or network, making it inaccessible to its intended users.

Denial of Service

to give a specific kind of protection to system resources; implement security policies by security mechanisms.

SECURITY SERVICES

assurance that the communicating entity is the one that it claims to be.

Authentication

provided for use at the establishment of, or at times during the data transfer phase of, a connection.

Peer Entity Authentication

is a property that a message has not been modified while in transit.

Data Origin Authentication

dictates who's allowed to access; is a security measure which is put in place to regulate the individuals that can view, use, or have access to a restricted environment.

Access Control

deals with protecting against the disclosure of information by ensuring that the data is limited to those authorized.

Data Confidentiality

refers to the accuracy and consistency of data stored in a database.

Data Integrity

refers to the assurance that the owner of a signature key pair cannot convincingly deny having signed the data.

Non-Repudiation

deals with hiding and covering of data which helps data to become confidential.

Encipherment

cryptographic value that is calculated from the data and a secret key known only by the signer.

Digital signature

intended to ensure the identity of an entity by means of information exchange.

Authentication exchange

produces cipher text output continuously, even in the absence of the plain text.

Traffic padding

means selecting and continuously changing different available routes between sender and receiver.

Routing control

involves use of trusted third party in communication.

Notarization

is perceived to be correct with respect to some criteria

Trusted functionality

the marking bound to a resource that names or designates the security attributes of that resource.

Security label

detection of security-relevant events.

Event detection

data collected and potentially used to facilitate a security audit.

Security audit trail

deals with requests from mechanism, such as event handling and takes recovery actions.

Security recovery

is the science of secret, or hidden writing.

Cryptography

practice of hiding messages

Encryption

is a method for encrypting messages.

Cipher

the key for encryption and decryptions are the same.

Symmetric Algorithms

encrypt data one block at a time (typically 64 bits, or 128 bits); used for a single message.

Block Ciphers

encrypt data one bit or one byte at a time; used if data is a constant stream of information.

Stream Ciphers

is determined by the size of the key.

Key Strength

is a method in which each letter in the alphabet is rotated by three letters.

Caesar Cipher

uses a sequence of monoalphabetic ciphers in tandem; (Blaise de Vigenere)

Polyalphabetic Caesar Cipher

this involves rearrangement of characters on the plain text into columns.

Columnar Transposition

the amount of secrecy needed should determine the amount of labor appropriate for the encryption and decryption.

Shannon’s Characteristics of “Good” Ciphers -

it is based on sound mathematics.

Properties of Trustworthy Systems

is the process of breaking an encryption code.

CRYPTANALYSIS

goal of DES is to completely scramble the data and key so that every bit of cipher text depends on every bit of data and every bit of key

Data Encryption Standard (DES)

Any exposure to the secret key compromise secrecy of ciphertext; a key needs to be delivered to the recipient of the coded message for it to be deciphered.

Symmetric Encryption

uses a pair of keys for encryption (Public key for encryption & Private key for decryption).

Asymmetric Encryption

developed by Ron Rivest, Adi Shamir, Len Adelman; both public and private key are interchangeable; variable Key Size (512, 1024, or 2048 buts); most popular public key algorithm.

RSA

developed by Taher ElGamal; variable key size (512 or 1024 bits); less common than RSA, used in protocols like PGP

El Gamal

hacker could generate a key pair, give the public key away and tell everybody, that it belongs to somebody else.

Man-in-the-middle Attack

used to improve efficiency.

Session-Key Encryption

Pretty Good Privacy (PGP), Secure/Multipurpose Internet Mail Extension (S/MIME), Secure Socket Layer (SSL) and Transport Layer Socket (TLS).

Encryption Protocols

is a method to create secret key by exchanging only public keys.

Key Agreement

is the process of validating the identity of a user or the integrity of a piece of data.

Authentication

is a fingerprint for a document.

Message digest

a message digest created with a key.

Message Authentication Codes

password is secret character string only known to user and server.

Password Authentication

set of rules that governs the communication of data related to authentication between the server and the user

Authentication Protocols

is an authentication service that uses symmetric key encryption and a key distribution center.

Kerberos

are hardware devices that generate unique strings that are usually used in conjunction with passwords for authentication.

Personal Tokens

uses certain biological characteristics for authentication (Fingerprint, Voice, Handwriting, Face, Hand Geometry Recognition, Retinal Scan).

Biometrics

scanning process takes advantage of the natural patterns in people's irises, digitizing them for identification purposes.

Iris Recognition

is a data item which accompanies or is logically associated with a digitally encoded message

Digital Signature

is a signed statement by a trusted party that another party’s public key belongs to them.

Digital Certificate

is the practice of signing a certificate with another private key that has a certificate for its public key.

Certificates Chaining