Apply wireless transmission security (WEP, WPA)

Communications Technology – Wireless Transmission Security (WEP, WPA, WPA2, WPA3)

Learning Objective

Apply knowledge of wireless transmission methods and security protocols (WEP, WPA, WPA2, WPA3) to configure, evaluate and improve the security of a wireless network, in line with Cambridge International AS & A Level IT 9626 (2025‑2027).

1. Why Wireless Security Is Required

• Radio‑frequency signals extend beyond the physical walls of a building, exposing the network to anyone within range.
• Unauthorised users can intercept, modify, replay or inject data packets.
• Regulatory, organisational and data‑protection policies demand protection of confidential information.

2. Wireless Transmission Methods (Syllabus 14.7)

2.1 Wi‑Fi (IEEE 802.11)

• Typical use‑cases: LANs, public hotspots, IoT gateways.
• Security concerns: susceptible to eavesdropping, rogue‑AP attacks, KRACK, and WPS abuse – mitigated by WPA3‑SAE and Protected Management Frames.

2.2 Bluetooth

• Typical use‑cases: peripheral connections, wearable devices, short‑range data exchange.
• Security concerns: pairing attacks (e.g., “Just Works” vulnerability), Bluetooth Low Energy (BLE) sniffing – mitigated by Secure Simple Pairing (SSP) and LE Secure Connections.

2.3 Infrared (IR)

• Typical use‑cases: remote controls, line‑of‑sight data links, short‑range sensor communication.
• Security concerns: limited to line‑of‑sight, but can be intercepted with a suitably placed receiver; physical shielding is the primary defence.

2.4 Microwave (point‑to‑point)

• Typical use‑cases: backhaul links, campus‑wide distribution, long‑distance outdoor links.
• Security concerns: interception with high‑gain directional antennas; encryption (e.g., AES‑CCMP) at the MAC layer is recommended.

2.5 Radio (UHF/VHF)

• Typical use‑cases: walkie‑talkies, RFID, low‑bandwidth IoT sensors.
• Security concerns: low data‑rate makes cryptographic protection optional, but simple stream ciphers or frequency‑hopping can raise the bar.

2.6 NFC (Near Field Communication)

• Typical use‑cases: contactless payments, device pairing, access control.
• Security concerns: eavesdropping is difficult due to ≤ 4 cm range, but relay attacks exist; use of ISO/IEC 14443 authentication and secure element storage mitigates risk.

3. Technical Parameters of Wireless Methods

4. Protocol Context (Syllabus 14.6)

Wi‑Fi security protocols operate at the IEEE 802.11 MAC layer (Layer 2 of the OSI model). Encrypted frames are carried over the physical layer and then encapsulated in the TCP/IP suite for end‑to‑end communication. Firewalls protect the wired side of the network, while WPA3’s Protected Management Frames (PMF) safeguard the wireless management traffic that firewalls cannot see.

5. Bandwidth, Media and Encryption (Syllabus 14.5)

The choice of wireless medium influences both raw bandwidth and the processing load of encryption. For example, the 5 GHz band offers higher data rates, making the additional CPU overhead of AES‑CCMP (WPA2/WPA3) negligible, whereas older 2.4 GHz devices with limited hardware may experience reduced throughput when using strong encryption.

6. Wireless Security Protocols

6.1 Wired Equivalent Privacy (WEP)

First security standard for IEEE 802.11. Uses RC4 stream cipher with a static secret key.

• How it works
  1. Secret key (40 bit or 104 bit) is concatenated with a 24‑bit Initialization Vector (IV).
  2. The combined key generates a per‑packet keystream via RC4.
  3. Keystream XOR‑ed with plaintext data.
• Weaknesses
  • IV is too short – collisions after ≈ 2²⁴ packets.
  • Static key enables statistical attacks (FMS, KoreK).
  • No integrity check – packets can be altered undetected.
  • Only 64‑bit or 128‑bit total key length – insecure by modern standards.
• Typical configuration steps
  1. Log into the router’s admin interface.
  2. Navigate to Wireless → Security.
  3. Select **WEP**, choose 64‑bit or 128‑bit, and enter a passphrase.
  4. Save settings and restart the router if required.
  5. Enter the same WEP key on every client device.

6.2 Wi‑Fi Protected Access (WPA – TKIP)

Interim improvement over WEP, introduced in 2003.

• Improvements
  • Temporal Key Integrity Protocol (TKIP) creates a per‑packet key from a dynamic 128‑bit master key.
  • 48‑bit Message Integrity Check (MIC) detects tampering.
  • Supports pre‑shared key (PSK) or 802.1X/EAP (Enterprise) authentication.
• Modes
  • WPA‑PSK – for homes/small offices.
  • WPA‑Enterprise – uses a RADIUS server for individual credentials.
• Typical WPA‑PSK configuration
  1. Log into the router’s admin console.
  2. Choose **WPA‑PSK** (or **WPA‑WPA2‑PSK** for mixed mode).
  3. Enter a strong passphrase (≥ 12 characters recommended).
  4. Select **TKIP** as the encryption algorithm.
  5. Save and reboot if prompted.
  6. Connect client devices using the same SSID and passphrase.

6.3 Wi‑Fi Protected Access 2 (WPA2 – AES/CCMP)

Current minimum standard for most deployments (since 2004). Replaces TKIP with the stronger AES‑based CCMP.

• Key improvements
  • 128‑bit AES encryption provides robust confidentiality.
  • CCMP (Counter Mode with CBC‑Message Authentication Code Protocol) supplies both encryption and integrity.
  • Supports the same PSK and Enterprise authentication models as WPA.
• Why WPA2 supersedes WPA
  • TKIP is deprecated; AES is resistant to known attacks.
  • Regulatory bodies (e.g., Wi‑Fi Alliance) require WPA2‑AES for certification.
• Configuration (WPA2‑PSK)
  1. Access the router’s security settings.
  2. Select **WPA2‑PSK** (or **WPA2/WPA‑PSK mixed mode** for legacy devices).
  3. Enter a complex passphrase (minimum 8 characters, preferably ≥ 12).
  4. Choose **AES** (or **CCMP**) as the encryption method.
  5. Save and apply the changes.

6.4 Wi‑Fi Protected Access 3 (WPA3)

Introduced in 2018; provides the strongest protection for compatible hardware.

• Key features
  • Simultaneous Authentication of Equals (SAE) – a password‑based Diffie‑Hellman exchange that resists offline dictionary attacks.
  • Protected Management Frames (PMF) – mandatory, preventing spoofed deauthentication/disassociation attacks.
  • Forward Secrecy – each session generates a fresh encryption key.
  • Optional 192‑bit security suite for enterprise environments.
• Configuration basics
  1. Choose **WPA3‑Personal** (SAE) or **WPA3‑Enterprise** (EAP‑192) in the router’s security menu.
  2. Enter a strong passphrase for Personal mode; configure a RADIUS server for Enterprise mode.
  3. Ensure the router’s firmware supports WPA3 and enable **PMF** if a separate toggle exists.
  4. Save settings and update client devices to the latest drivers/OS to support SAE.

7. Common Wireless Attacks & Mitigation Strategies

8. Comparison of Wireless Encryption Protocols

9. Glossary (AO1 – Terminology)