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What is pairwise master key caching?
Pairwise Master Key (PMK) caching and Opportunistic Key Caching (OKC) allow clients to roam without having to repeat the entire 802.1X authentication process.
What is PMK in networking?
A PMK is a cryptographic key which is used to derive lower level keys. Networks based on technologies such as UMTS and WiMAX use PMK as part of their relative security procedures.
How does opportunistic key caching work?
Opportunistic Key Caching (OKC) is an enhancement of the WPA2 Pairwise Master Key ID (PMKID) caching method, which is why it is also named Proactive or Opportunistic PMKID Caching. This is required to generate new encryption keys every time a client reassociates with APs.
What is derived pairwise master key?
The pairwise master key (PMK) may be derived from the AAA key. Pairwise Master Key (PMK) – The highest order key used within the 802.11i amendment. The PMK may be derived from an Extensible Authentication Protocol (EAP) method or may be obtained directly from a Preshared key (PSK).
What is the 4 way handshake?
A four-way handshake is a type of network authentication protocol established by IEEE-802.11i that involves standards set up for the construction and use of wireless local area networks (WLANs). The four-way handshake provides a secure authentication strategy for data delivered through network architectures.
What is Pmksa caching?
PMKSA caching enables fast authentication based on a PMK (and corresponding PMKID) that has been cached between two peers from a previous authentication. If the AP matches and selects a cached PMKID, it includes it in M1 of the 4-way handshake or the FILS Authentication frame response.
How PTK is derived?
From the PMK, the station and AP derive three keys using a pseudorandom function. The pseudorandom function first generates an intermediate key, the PTK. The pseudorandom function in the pairwise key hierarchy (see Figure 8-15) is the industry-standard SHA-1 cryptographic hash.
What is 802.11 i and what aspect of WLANs does it deal with?
802.11i is a standard for wireless local area networks (WLANs) that provides improved encryption for networks that use the popular 802.11a, 802.11b (which includes Wi-Fi) and 802.11g standards. However, AES requires a dedicated chip, and this may mean hardware upgrades for most existing Wi-Fi networks. …
What is the 4-way handshake?
Which out of the following is used to derive the pairwise master key?
The Pairwise master key (PMK) can be derived from either PSK or MSK.
Does WPA2 use 4-way handshake?
Imagine an access point is configured with WPA2/PSK and device is trying to connect to it. This is where 4-way handshake happens, instead of sending the password to the access points there are EAPOL (Extensible authentication protocol over LAN) messages exchange happens.
What is the four stage handshake used for?
When to use pairwise master key caching ( PMK )?
This technique is known as PMK (Pairwise Master Key) caching. When a client first associates to an AP under an 802.1X authentication architecture, an EAP exchange takes place, followed by a 4-way handshake to verify encryption keys. Using PMK caching, an AP can cache the PMK identifier of the EAP exchange,…
What are the security implications of Pairwise Master Key?
PMK caching is typically found in networks that have roaming features enabled and time-sensitive applications (e.g., VOIP) – applications that can’t risk disconnection because the client has to re-authenticate to the AP every time it roams. So the risk isn’t really very high.
What is opportunistic key caching in 802.11i?
An extension of this technique is known as OKC (Opportunistic Key Caching), a method not defined in 802.11i but necessary to enable optimized roaming at layer 2 for client devices moving between APs.