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Easy-Secure is a digital certificate-issuing authority (CA) - NSC Information Technology - Question 2 - 2017 - Paper 1
Question 2
Easy-Secure is a digital certificate-issuing authority (CA). Online traders can apply for a digital certificate. You need a program to test the validity of existing ... show full transcript
Worked Solution & Example Answer:Easy-Secure is a digital certificate-issuing authority (CA) - NSC Information Technology - Question 2 - 2017 - Paper 1
Step 1
2.1 Write code for a constructor method that will receive the name of the certificate holder, the expiry date, the security code and the issue number as parameters.
Answer
To create the constructor method, you would include parameters for the certificate holder's name, expiry date, security code, and issue number. The constructor will assign the values to the class attributes as follows:
public DCertificate(String cFertHolder, String expiryDate, String securityCode, int issueNr) {
this.cFertHolder = cFertHolder;
this.expiryDate = expiryDate;
this.securityCode = securityCode;
this.issueNr = issueNr;
}
Step 2
Step 3
2.1.3 Write code for a method called resetExpiryDate that will reset the expiry date attribute of the digital certificate to the new expiry date based on the system date.
Answer
To reset the expiry date to a date one year from now, the method can be implemented as follows:
public void resetExpiryDate() {
String currentDate = $SysDate;
// Assuming you have a method to add a year
this.expiryDate = addOneYearToDate(currentDate);
}
Step 4
2.1.4 Write code to complete the method called hasExpired that will determine whether the expiry date attribute of the certificate has expired or not.
Answer
The implementation for checking if the certificate has expired is:
public boolean hasExpired() {
// Convert string dates to comparable date types
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date expiry = sdf.parse(this.expiryDate);
Date current = sdf.parse($SysDate);
return current.after(expiry);
}
Step 5
2.1.5 Write code to complete the method called generateSecurityCode to compile a security code for the digital certificate.
Answer
The method to generate a security code may look like this:
public void generateSecurityCode() {
String characters = "0123456789ABCDEFG";
StringBuilder securityCode = new StringBuilder();
Random rand = new Random();
for (int i = 0; i < 10; i++) {
securityCode.append(characters.charAt(rand.nextInt(16)));
}
securityCode.append(":"); // Add colon
for (int i = 0; i < 4; i++) {
securityCode.append(characters.charAt(rand.nextInt(16)));
}
this.securityCode = securityCode.toString();
}
Step 6
2.1.6 Write code to complete the given toString method that will return a string with attributes in the following format.
Answer
The toString method can be written as follows:
@Override
public String toString() {
return "Digital certificate information:\n" +
"Certificate holder: " + cFertHolder + "\n" +
"Expiry date: " + expiryDate + "\n" +
"Security code: " + securityCode + "\n" +
"Issue number: " + issueNr;
}
Step 7
2.2.1 Write code to search for the name of the certificate holder in the text file.
Answer
To implement the search, the code can be structured as follows:
public void searchCertificateHolder(String holderName) {
boolean found = false;
// Read from the text file, error handling here...
// If found, instantiate objDigCert and set pnq2_Buttons
if (found) {
objDigCert = new objDigCert(...);
pnq2_Buttons.setVisible(true);
} else {
System.out.println("No digital certificate issued.");
pnq2_Buttons.setVisible(false);
}
}
Step 8
2.2.2 Write code to clear output area and display info using toString method.
Answer
To clear the output area and display the certificate information, you can implement:
public void displayCertificateInfo() {
redOutput.setText(""); // Clear output area
redOutput.setText(objDigCert.toString());
}
Step 9
2.2.3 Write code to determine if the certificate has expired and display a message.
Answer
This method will check for expiration and handle user interaction as follows:
public void checkValidity() {
if (objDigCert.hasExpired()) {
// Ask user if to renew
// Renew logic to be handled here...
} else {
System.out.println("The digital certificate is valid.");
}
}