Pmk

Definition

The Pairwise Master Key (PMK) is a cryptographic key used in wireless networking protocols, specifically in WPA and WPA2 security standards. The PMK is derived from the Pre-Shared Key (PSK) and is essential for establishing secure communications between a client and an access point. It plays a critical role in the key management process, enabling both authentication and encryption of data during transmission.

5 Must Know Facts For Your Next Test

1. The PMK is generated during the initial connection phase when a client connects to a wireless network using WPA or WPA2.
2. This key serves as the basis for creating session keys that are unique for each session, enhancing security against replay attacks.
3. The PMK is not transmitted over the air, which helps to protect it from eavesdroppers and potential attackers.
4. In WPA2, the PMK is derived from the PSK using a hashing function, ensuring that even if the PSK is compromised, generating the PMK remains difficult without additional information.
5. Proper management of the PMK is crucial for maintaining secure wireless communications and preventing unauthorized access to network resources.

Review Questions

• Explain how the Pairwise Master Key (PMK) is generated and its significance in securing wireless communications.
  • The PMK is generated when a client connects to a wireless network using WPA or WPA2, typically derived from the Pre-Shared Key (PSK) through a hashing process. This key is significant because it establishes a secure link between the client and access point by facilitating encryption and authentication. By ensuring that session keys created from the PMK are unique for each connection, the risk of replay attacks is minimized, enhancing overall security.
• Discuss the role of the Four-Way Handshake in relation to the PMK and its importance for establishing secure connections in wireless networks.
  • The Four-Way Handshake is a crucial process that takes place when a client attempts to connect to a wireless network secured by WPA or WPA2. This handshake uses the PMK to confirm that both the client and access point share the same credentials and subsequently generates fresh session keys for encrypting data. The Four-Way Handshake also ensures mutual authentication, verifying that both parties are legitimate before any sensitive data is exchanged.
• Evaluate how the security of the PMK impacts overall wireless network security and what measures can be taken to protect it from potential threats.
  • The security of the PMK directly influences wireless network integrity since it underpins session keys used for encryption. If an attacker gains access to the PMK, they can decrypt all traffic transmitted during that session. To protect the PMK, it is essential to use strong PSKs and implement robust authentication mechanisms. Additionally, regularly changing PSKs and using enterprise-level solutions like 802.1X can enhance security by minimizing risks associated with key compromise.

Related terms

Pre-Shared Key (PSK): A shared secret used in WPA and WPA2 protocols to authenticate users before establishing a secure connection.

Four-Way Handshake: A process that occurs during the initial connection setup in WPA/WPA2, which ensures that both the client and access point can agree on a shared session key based on the PMK.

Group Temporal Key (GTK): A key used to encrypt multicast traffic sent to multiple clients on a wireless network, which is also derived during the key management process alongside the PMK.