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
