Chapter 1 Flashcards
Data?
Raw numbers, letters, symbols, sounds, images with no meaning
Information
When you add context and meaning to data it becomes information
Direct Data Source
Data will be collected for the purpose which it will be used for.
Primary Source
Relevant data
Up to date
Bias eliminated
Source is know - trusted
Takes long time to collect
Difficult to collect
Indirect Data Source
Data that was collected for a different purpose.
Secondary source
Immediately available
Large samples of data
Additional data
Not up to date
Unknown source
Biased data
Encryption
The scrambling of data so it cannot be understood without a decryption key to make it unreadable if intercepted.
Caesar (Shift) Cipher
Selects replacement letters by shifting along the alphabet. Ciphers convert a message to an encrypted message.
Symmetric encryption
Requires both the sender and recipient to possess a private key. This key can be sent to the recipient at a later date via post or mail.
Asymmetric encryption
(Public key cryptography)
There is a public key which is available to anyone who wants to send data and a private key known only to the recipient. In order to find a public key a digital certificate is required. Used for SSL layer.
Digital certificates
Identifies the user or server and provides the public key
Quality of Information
Accuracy
Age
Level of detail
Completeness
Relevance
What does a digital certificate have?
Organisation name
Organisation that issued the certificate.
User’s email address
User’s country
User’s public key
SSL [Secure sockets layer]
It is a protocol that provides secure communication over the internet. Asymmetric encryption is used for SSL, and provides both server and client authentication.
TLS [Transport layer security]
It is the modern and more secure replacement of SSL.
HTTPS
[Hypertext transfer protocol SECURE]
Is an extension of the Hypertext Transfer Protocol. It uses encryption for secure communication over a computer network, and is widely used on the Internet.
Web pages that use HTTPS have “https://” and a padlock symbol.
Validation
The process of checking that the data matches acceptable rules. Validation does not mean that the data is correct.
Presence check
Used to ensure that data is entered, if data is entered, then it is accepted.
Range check
Ensures that data is within a defined range and has two boundaries (lower and upper). <, >, =, >=, <= are used.
Type check
Ensures that data must be of a defined data type.
Length check
Ensures that data is of a defined length or within a range of lengths.
Format check [Picture check]
Ensures data matches a defined format.
Lookup check
Tests to see if the data exists in a list.
Consistency check
Compares data in one field with data in another field that already exists within a record, to check whether both are consistent with each other.
Check digit
It is a number (or letter) that is added to the end of an identification number being input.
Verification
Ensuring data entered into the system matches the original source.
