Computer Science for IGCSE & O level - Data Transmission (Section 11)
1
What does 'ciphertext' refer to in the context of cryptography?
Trả lời(C)
The encrypted form of the data.
2
What is one way that the sender knows the data has been successfully delivered?
Trả lời(B)
The receiver acknowledges the data.
3
What is the main purpose of a hashing algorithm?
Trả lời(B)
To verify data integrity.
4
In the ISBN-13 calculation, what is done after calculating the remainder?
5
What do you call the process of converting data from a readable format to an unreadable format?
6
Which of the following is an error detection mechanism?
8
What is the main goal of an error detection code?
Trả lời(B)
To ensure data has arrived correctly.
9
If you are using odd parity and the data byte is 01100011, what will the parity bit be?
10
What typically constitutes a data packet?
11
What is the primary goal of error detection codes?
Trả lời(B)
To identify if any errors occurred during transmission.
12
What does the term 'payload' represent within a data packet?
Trả lời(B)
The actual data being transmitted.
13
What is the benefit of using a digital signature?
Trả lời(C)
It guarantees message authenticity and non-repudiation.
14
What type of key is shared in symmetric encryption?
15
What is a defining characteristic of symmetric encryption?
Trả lời(C)
It's generally faster and simpler.
16
In packet switching, the 'hop number' indicates what?
Trả lời(B)
The number of routers a packet has already passed through.
17
What type of encryption is generally faster and simpler?
18
Which of the following is NOT a form of error detection?
19
What is the main benefit of serial data transmission?
20
What is the main function of a USB connector?
Trả lời(B)
To provide a universal interface for connecting devices.
21
What is the principal mechanism utilized by ARQ to ensure reliable data transmission?
22
What is a 'trailer' in the context of data packets?
Trả lời(C)
Information used to detect errors in transmission.
23
What is the primary aim of symmetric encryption?
Trả lời(B)
To establish a secure communication channel.
24
In which mode does data transmission occur in only one direction?
25
What does a digital signature provide?
26
In symmetric encryption, what is the primary requirement for secure data transmission?
27
How are checksums typically calculated?
Trả lời(B)
By adding up the data values and taking the remainder after division by a certain number.
28
What is the main advantage of using a digital signature?
Trả lời(A)
Ensures data has not been altered.
29
What is the main goal of using checksums in data communication?
Trả lời(B)
To ensure the data's integrity.
30
What is used to decrypt data in asymmetric encryption?
31
In the context of data transmission, what does 'ARQ' stand for?
32
Which method is used to convert the data to an unreadable format?
33
In the context of data transmission, what does 'ARQ' stand for?
34
What is the purpose of using a public key?
35
What is the major security consideration when using symmetric encryption?
36
Which type of encryption uses a single key for both encryption and decryption?
37
What is the purpose of a 'sequence number' in a packet?
Trả lời(C)
To ensure packets are reassembled in the correct order.
38
What does a router do in packet switching?
Trả lời(C)
Decides where to send the next packet.
39
What is the role of encryption in data security?
Trả lời(C)
To protect data from unauthorized access.
40
What is the significance of a 'positive acknowledgement' in ARQ?
Trả lời(A)
It means the data has been received correctly.
41
What is a key used for in cryptography?
Trả lời(B)
To transform data into ciphertext and back.
42
Which of the following can cause data corruption during transmission?
43
What is one of the benefits of USB-C compared to older USB versions?
Trả lời(C)
Provides higher power delivery capabilities.
44
What is the main function of error detection codes?
Trả lời(C)
To identify changes in the data.
45
What distinguishes half-duplex from full-duplex data transmission?
Trả lời(B)
Half-duplex transmits data in one direction at a time; full-duplex transmits in both directions simultaneously.
46
Which of the following methods uses an extra bit added to a byte to ensure an even or odd number of 1s or add number of 1?
47
What is the primary function of a hashing algorithm?
Trả lời(C)
To create a unique 'fingerprint' of data.
48
The secrecy of which element is most critical in symmetric encryption?
49
In the ISBN-13 system, what is the purpose of the check digit?
Trả lời(B)
To verify the validity of the ISBN.
50
What is the role of a 'timeout' in ARQ?
Trả lời(B)
To retransmit data if no acknowledgement is received.
