← IGCSE Computer Science Paper 1

HTTP compared with HTTPS

HTTP plus SSL/TLS encryption. Plain HTTP sends readable text that can be intercepted; HTTPS scrambles data so intercepted data can't be read, and a certificate shows the site is genuine.

Part of: IGCSE Computer Science 0478 — 5.1 The Internet and the World Wide Web — Module 16, ACARA Digital Technologies Years 7–8 — Wired and Wireless Networks — Module 37, ACARA Digital Technologies Years 9–10 — Networked Systems and Access Control — Module 87, QCE Digital Solutions Unit 4 — Digital Methods for Exchanging Data — Module 95, WA Computer Science ATAR Year 11 — Network Communications — Module 106, WA Computer Science ATAR Year 11 — Cyber Security — Module 93

Understanding HTTP compared with HTTPS in IGCSE Computer Science Paper 1

What it does: Pages that handle sensitive data need HTTPS so the data is encrypted when it travels across the internet. HTTP does not encrypt data, so anyone who intercepts it can read it. HTTPS encrypts it first. A digital certificate is used with HTTPS to show the site is who it says it is, not a fake copy. SSL/TLS is the security layer that encrypts the data. Cookies are a separate topic. The https:// protocol adds SSL/TLS encryption, so any intercepted data is scrambled and unreadable.

Common mistakes: An HTTPS address means SSL/TLS is used, so the data is encrypted. Line 3 should be 'encrypt data with SSL/TLS', not send it as plain text. A payment page must use HTTPS so the card details are encrypted and the padlock shows. The URL should start with https://, not http://.

Class: _____________________ · Name: _____________________ · Date: _________

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This module's key terms are also in a printable crossword (Modules 464–476) and word search (Modules 464–489).

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Learning

Duo

Which protocol sends data as readable plain text?

HTTPHTTPS

Matches

Enter card details on http://shop.com/pay because HTTP encrypts the data

↓

HTTP does not encrypt data. It sends plain text that can be intercepted. A payment page needs HTTPS.

Applying

Meanings

Term

HTTPS

Meaning

HTTP plus SSL/TLS encryption. Plain HTTP sends readable text that can be intercepted; HTTPS scrambles data so intercepted data can't be read, and a certificate shows the site is genuine.

Practice

http://shop.com/pay -> plain text, can be intercepted

Testing

Gaps

://www.mybank.com/login.html

Check Answer

Spots

2IF url STARTS "https" THEN

3 send data as plain text

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Quick Questions

1. Which protocol sends data as readable plain text?

A. HTTPS

B. HTTP ✓

HTTP does not encrypt data, so anyone who intercepts it can read it. HTTPS encrypts it first.

2. What does HTTPS add to HTTP?

A. A faster internet connection

B. SSL/TLS encryption ✓

The S stands for secure. SSL/TLS is the security layer that encrypts the data. It does not make the connection faster.

3. A hacker intercepts data sent over HTTPS. What do they see?

A. Scrambled data they cannot read ✓

B. The password in plain text

HTTPS encrypts data, so intercepted data looks scrambled and is useless without the key.

4. Which page should definitely use HTTPS?

A. A payment page that takes card details ✓

B. A page of public opening times

5. What does a digital certificate show about a website?

A. The website is genuine ✓

B. The website has no adverts

A digital certificate is used with HTTPS to show the site is who it says it is, not a fake copy.

Match the Pairs

http://school-shop.com/login → Data is sent as plain readable text, so anyone who intercepts it can read it

https://school-shop.com/login → Data is encrypted using SSL/TLS, so intercepted data cannot be read

A login or payment page should use the secure protocol so passwords and card numbers are protected → https://bank.com/payment

The security layer that HTTPS adds to HTTP to encrypt the data → SSL/TLS

Enter card details on http://shop.com/pay because HTTP encrypts the data → HTTP does not encrypt data. It sends plain text that can be intercepted. A payment page needs HTTPS.

HTTPS is secure because it sends data as plain text → HTTPS does not send plain text. It encrypts data with SSL/TLS so intercepted data cannot be read.

Key Term

HTTPS

HTTP plus SSL/TLS encryption. Plain HTTP sends readable text that can be intercepted; HTTPS scrambles data so intercepted data can't be read, and a certificate shows the site is genuine.

Fill in the Blanks

1. https://www.mybank.com/login.html

Hint: Type the protocol name that encrypts data, so a login page is safe to use.

2. HTTPS = HTTP + SSL/TLS

Hint: Type the security layer added to HTTP to encrypt data (two names joined by a slash).

3. IF page = "payment" THEN use HTTPS

Hint: Type the protocol that payment pages need to protect card details.

4. HTTPS site shows a digital certificate

Hint: Type the word for what proves that a website is genuine.

5. http data is sent as plain text

Hint: Type the word describing readable, unencrypted text that can be intercepted.

Spot the Error

Question 1

A url ← "https://shop.com/pay"

B IF url STARTS "https" THEN

C send data as plain text

D ENDIF

Line C — An HTTPS address means SSL/TLS is used, so the data is encrypted. Line 3 should be 'encrypt data with SSL/TLS', not send it as plain text.

Question 2

A url ← "http://bank.com/pay"

B IF url STARTS "https" THEN

C OUTPUT "Padlock shown"

D ENDIF

Line A — A payment page must use HTTPS so the card details are encrypted and the padlock shows. The URL should start with https://, not http://.

Question 3

A IF page = "payment" THEN

B protocol ← "HTTP"

C ENDIF

Line B — Payment and login pages need HTTPS so that the data is encrypted. The protocol should be "HTTPS", because plain HTTP is not secure.

Question 4

A browser requests the page

B server sends its cookie

C IF certificate valid THEN

D OUTPUT "Site is genuine"

Line B — The server proves it is genuine by sending its digital certificate. A cookie does not prove the site is genuine, so line 2 should say 'certificate'.

Question 5

A hacker INTERCEPTS data

B IF protocol = "HTTPS" THEN

C data is scrambled

D hacker can read it easily

E ENDIF

Line D — With HTTPS the data is encrypted, so an intercepted copy is scrambled and cannot be read. Line 4 should say the hacker cannot read it.

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