1.3 Exchanging data extra Flashcards
Explain some reasons there might appear to still be duplicates when hashing with images
Hashing works on the data / bits (1)
and so two images may appear the
same but not be identical at a bit level
(1). This could be because they are
different file types (1) / different sizes
(1). Even the change of a single bit
may result in a completely different
hash (1)
Lossy compression on text
Text loss means it will be undreadable
For dictionary coding, instead of tokens what word should you use
Tokens or smaller groups of characters
Explain why asymmetric encryption is more suited to transactions over the internet than symmetric encryption
Any four from:
Symmetric encryption would require both
parties to have copy of the key (1) this
couldn’t be transmitted over the internet or
an eavesdropper monitoring the message
may see it (1) Asymmetric gets round this
requirement as there are two different keys
(1) One key encrypts the data (1) which
can be publically distributed (1) and a
different key to decrypt it (1) which is kept
private (1
What is a primary key
A field that has a unique value / a
unique identifier (1) for every record in
that table (1)
What is the problem with many to many relationships
They are not allowed in 3NF
Give one advantage and one disadvantage of indexing the field Artis
+Searches of artist can be performed more quickly
-The index takes up extra space in the database
State what is meant by an IP address
A numerical address made of 4 numbers
each between 0 and 255 / 32 hexadecimal
digits (1)
That uniquely identifies a device on a
network. (1)
What type of identifier is an IP adress
It is a logical identifier (i.e. can change on a
physical device) (1)
What is meant by the term hash
A result generated by applying an
algorithm / numeric process to a value. (1)
What is a bridge
–Provides a link between (local area)
networks
–To connect the student and / or teacher
and / or administration networks together.
What is a gateway
–Provides a link between two dissimilar
networks
–Links the school networks to the Internet
Firewalls
Restrict access to websites and applications
Where does client side processing take plac e
Client side processing takes place in the
web browser.
Where does server side processing take place
on the
webserver. Data is sent from the browser
to the server, the server processes it and
sends the output back to the browser
What does client side processing not require
Data to be sent back and forth meaning code is much more responsive
Is code visible or invisible with client side processing
Code is visible which means it can be
copied
What does server side processing take away
the
reliance of the browser having the correct
interpreter
Is code invisible or visible to the user with server side processing
It hides the code from the user,
protecting copyright and avoiding it being
amended/circumvented
Disadvantage of server side processing
Server side
processing puts extra load on the server.
This is at the cost of the company hosting
the website
When is client side processing best used
Client side processing is best used when
it’s not critical code that runs or where a quick response is needed
When is server side processing best used
Server side processing is best used where
it is integral that processing is carried out.
It is often used for generating content
When is server side processing often used
to access data including
secure data. For this reason any data
passed to it has to be checked carefully
What do hackers get access to in relation to hash
The hash value which cannot be reversed to the key
What is HTTP?
An application layer protocol that facilitates clients requesting information from servers. Each HTTP request by a client expects a HTTP response from the server.
What are the Get and Post requests?
The two main types of HTTP request. Get requests are supposed to be harmless and repeatable and can be bookmarked. Post requests are for when a change is meant occur (e.g. create, update or destroy operations).
What is the URL (Uniform Resource Locator)?
A text string that represents a destination for a HTTP (or other protocol) request.
What is the API (Application Programmers Interface)?
series of functions or protocol endpoints that allow applications to access the features of another system.
What is web api
modern approach to server side processing. Web APIs send unformatted data to the client on demand and the client decides how to render it.
What is client side processing
When the client generates content based on a data requested from the server. See JavaScript…
How does javascript allow dynamic web pages
Modern JavaScript can execute HTTP requests without the need to reload the page. This makes it possible to create dynamic web applications
Uses of server side processing on the web
Accessing a database
Security and authentication
Search engines
Cloud services
Hosting APIs (see later slides)
Uses of server side processing elsewhere
Traditional file storage (e.g. a NAS)
Infrastructure (for LANs and WANs)
Virtual machines for thin clients
Advantages of server side processing
Can access secure data and control what the client sees.
Should be far more secure against code manipulation.
The server is probably more powerful than the client so can potentially tackle heavy workloads in less time.
Uses of Client side on web side?
Interactivity without page reloads
Validation rules
Animations, games, etc.
Responsive design
Any ‘offline’ abilities
Traditional desktop apps
Any processing in mobile apps
Video games (apart from Stadia!)
