Exchanging data and encryption Flashcards
what is the purpose of compression ?
and the benefits ?
To reduce the amount of data to send or store
Benefits:
-Data is sent more quickly
-less storage is required
what are the different types of compression ?
-Lossy - non essential data is permanetly removed
-lossless- Patterns in the data are spotted and summerized in a shorter format ; without permanetly removing any information
what are the different types of Lossless Compression :
-RLE (Run length Encoding)
A basic method of compression that summerises consecutive patterns of the same data
-Dictionary Compression
Spots reguarly Occuring data and stores it seperatly in a dictionary
what is Encryption?
A way of making sure data cannot be understood , if you dont possess the means to decrypt
what is Caesar Cipher ?
the Caesar cipher is the most basic type of encryption and the most insecure
what is brute fore attack ?
Tries all the possible combinations to attempt to decrypt ciphertext until one works
what is frequency Analysis ?
letters are not used equally often
what is Vernham cipher ?
and ADV and DIS-adv?
- Vernham cipher is the most secure type of encrpytion , this generates an OTP that is unique
ADV:
-most secure encryption
dis-adv:
-true random number is diffucult to acheive
-the key mus be shared secretly
-they key must be as long as text
what is an entitiy?
- An entitiy is a category of object, person, event to thing of intrest about which data needs to be recorded
what is a primary key ?
what is a secondary key ?
what is a foreign key ?
primary key - is a unique identifier for each record in a table
secondary key - allows a database to be searched quickly
foreign key - a foreign key is the attribute which links two tables together
what is a composite primary key?
a composite primary key is two or more primary keys in a table
name the three entity relationships ?
- one to one = husband to wife
- one to many = mother to kids
- many to many = actor to films
what is suitable for lossy and lossess?
Lossy:
- Audio
-Images
-video
Lossless:
-Documents
-files
explain how asymmetric information works ?
The role of asymmertic information works is that both the sender and receiver have a public key, which is used to encrypt the data, both public keys are available to both parties, an accessible by anyone. Then a private key, which is used to decrypt the data, is only available to the specific recipient,
what is a public key
what is a private key
a Public key is a key that is used to encrypt data( this is avaliable to anyone , and is sent to the receiver)
a private key is a key that is used to dycrpt data( the recipient only has access to there own private key)
