How many QCAA Digital Solutions questions cover Prototype digital data exchanges?

AusGrader has 33 QCAA Digital Solutions questions on Prototype digital data exchanges, all with instant AI grading and detailed marking feedback.

QCAA (QCE) Digital Solutions — Prototype digital data exchanges Questions & Answers | AusGrader

Q2

2024

QCAA

1 mark

Q2

1 mark

A retail store uses facial recognition to send text messages about sale items to consenting customers while they are in the store.

This use of data personally impacts customers through

A

invasion of privacy.

B

increased data accuracy.

C

improved store inventory management.

D

a more personalised shopping experience.

Q3

2024

QCAA

1 mark

Q3

1 mark

How could a developer refine the following algorithm to improve maintainability?

/* Calculate the average value of an input array */
0 START
1     INPUT x AS ARRAY
2     SET sum = 0
3     FOR n IN x
4         sum = sum + n
5     ENDFOR
6     CALCULATE result = sum / length of x
7     OUTPUT result
8 END

A

Use an error-checking function.

B

Write code comments on every line.

C

Rename variables n, x and result to be more descriptive.

D

Incorporate a function from an available code library to sum the array.

Q13

2021

QCAA

5 marks

Q13

In an online silent auction, items are posted on a public website and participants post a secret bid on the items they would like to purchase. Bidders cannot see each other’s bids. The bidding period is 7 consecutive days.
At the end of the auction, all bid values are revealed on the website and the highest bidder pays the amount they posted to obtain the item.

Q13a

3 marks

Explain how checksums, encryption and authentication would improve the security of the data exchange in this scenario.

A checksum algorithm would be used to inspect the binary representation of auction data. If the checksum from the user is different from the checksum on the server, it means that the data has been corrupted or manipulated.

Encryption would be used to scramble the auction data to make it impossible to read in transit, but allowing it to be decrypted by the authorised recipient with a secret key.

Authentication would be used to verify the identity of the participant by using a digital signature or authentication code. A digital signature confirms that the bidder is who they say they are.

Marking Criteria

Descriptor	Marks
Explains how the security of the data exchange would be improved through checksums	1
Explains how the security of the data exchange would be improved through encryption	1
Explains how the security of the data exchange would be improved through authentication	1

Q13b

2 marks

Recommend one encryption method to securely store auction data and justify your response.

I would recommend AES for encrypting auction data to avoid a security breach. AES supersedes DES and 3DES and uses 128-bit blocks with 128, 192 and 256-bit encryption keys, whereas DES and 3DES use 64-bit blocks and key encryption. DES and 3DES are older ciphers and easily cracked in as little as one day, which would provide an opportunity for a hacker to gain access to auction data before the bids are revealed.

Marking Criteria

Descriptor	Marks
Recommends a valid encryption method	1
Effectively justifies the recommended encryption method	1

Q13

2022

QCAA

12 marks

Q13

Refer to Stimulus 2 in the stimulus book.

Q13a

7 marks

Use pseudocode to symbolise a one-time pad encryption algorithm with any lower case letters. Users must input the plain text and key.

Marking Criteria

Descriptor	Marks
Symbolises, without logic errors, an algorithmic statement for user input of text	1
Symbolises, without logic errors, an algorithmic statement for user input of key	1
Symbolises, without logic errors, an algorithmic statement for 'indexOf' sub-procedure	1
Symbolises, without logic errors, an algorithmic statement for 'lengthOf' sub-procedure	1
Symbolises, without logic errors, an algorithmic statement for 'checkLowerCase' sub-procedure	1
Symbolises, without logic errors, an algorithmic statement for 'lowerCaseAlphabet'	1
Effectively uses pseudocode conventions	1

Q13b

5 marks

Evaluate the encryption algorithm developed in Question 13a) by performing a desk check. Use the plain text and key provided. Specify all inputs and outputs in table form.

Plain text: Queens
Key: ryjwah
Example output: hsnanz

userText = queens
opyKey = ryjwah

Letter of userText = q u e e n s
userText letter index= 16 20 4 4 13 18

Letter of optKey = r y j w a h
otpKey letter index = 17 24 9 22 0 7

Encryption index = 7 18 13 0 13 25
cipherOutput = h s n a n z

Marking Criteria

Descriptor	Marks
Demonstrates accurate use of one programming feature that specifies all inputs and outputs in table form	1
Demonstrates accurate use of a second programming feature that specifies all inputs and outputs in table form	1
Demonstrates accurate use of a third programming feature that specifies all inputs and outputs in table form	1
Demonstrates accurate use of a fourth programming feature that specifies all inputs and outputs in table form	1
Demonstrates accurate use of a fifth programming feature that specifies all inputs and outputs in table form	1

Q12

2022

QCAA

8 marks

Q12

Refer to Stimulus 1 in the stimulus book.

Q12a

6 marks

Describe the listed algorithm constructs and identify one example of each from the stimulus. Use corresponding line numbers to identify examples.

Assignment:

Example:

Condition:

Example:

Iteration:

Example:

Assignment: A value (stated or calculated) stored in a variable/memory location.
Example: Line 13, value = 0.04.

Condition: A comparison that retrieves a true or false value (or the value of a Boolean variable).
Example: Line 12, IF depositAmount <= 10000.

Iteration: A group of algorithmic statements that are repeated while a condition is met.
Example: Lines 25–27

FOR i = 0 TO years
deposit = depositAmount + depositAmount x interestRate
NEXT i

Marking Criteria

Descriptor	Marks
Describes assignment	1
Describes iteration	1
Describes condition	1
Identifies an example of assignment	1
Identifies an example of condition	1
Identifies an example of iteration	1

Q12b

2 marks

Explain the purpose of modularisation and identify an example of how it is used in the stimulus. Use corresponding line numbers in your response.

Modularisation breaks sections of code into smaller chunks so the algorithm is easier to understand, and allows the same code to be used in different parts of the application. For example, calculateInterestRate is a separate module (lines 11–22) and is called/used at line 5. It returns a value (line 21) which is stored in interestRate (line 5).

Marking Criteria

Descriptor	Marks
Explains the purpose of modularisation	1
Identifies an example of how modularisation is used	1

QCAA Digital Solutions Prototype digital data exchanges

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