What does PSK stand for?
PSK stands for Pre-shared Key. A secret shared in advance by both ends of a connection, such as the Wi-Fi passphrase in WPA2-Personal or the key for an IPsec tunnel. One key for everyone is easy to deploy but hard to revoke; enterprise networks use 802.1X instead.
A pre-shared key is a secret that both sides already hold before they connect. On Wi-Fi it is the network password: in WPA2-Personal every device proves it knows the passphrase, and the encryption keys are derived from it. It is simple and needs no server, which suits homes and small offices. The cost is that everyone shares one secret: it cannot be withdrawn from one person without changing it for all. Pre-shared keys are also used to authenticate site-to-site VPN tunnels.
PSK in practice: an example
A small office uses one Wi-Fi passphrase for twelve staff. When an employee leaves, the only way to remove that person's access is to change the passphrase on the access point and on every remaining device.
What PSK is confused with
PSK vs SAE: what is the difference?
SAE is the handshake WPA3-Personal uses in place of the WPA2 pre-shared key exchange. Users still type a password, but an attacker who records the handshake cannot test password guesses offline.
PSK vs 802.1X: what is the difference?
With a PSK everyone shares one secret. With 802.1X, the Enterprise mode, each user signs in with their own credentials checked by a RADIUS server, so one account can be disabled without touching the others.
Which exams cover PSK?
PSK is on the official CompTIA acronym list for one of the four exams covered here.
- Network+ N10-009: 2.0 (Network Implementation).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A company wants to be able to cut off one person's Wi-Fi access without changing anything for other users. What should replace the shared passphrase?
- 802.1X with a RADIUS server
- A longer pre-shared key
- Hiding the SSID
- MAC filtering only
Show the answer
A. 802.1X with a RADIUS server. 802.1X gives every user individual credentials. Any shared key, however long, has to be changed for everyone to exclude one person.
2. Why is a short WPA2 pre-shared key dangerous even though the traffic is encrypted?
- A captured handshake lets an attacker test password guesses offline
- The key is sent in clear text in every frame
- Short keys switch encryption off
- The access point broadcasts the key
Show the answer
A. A captured handshake lets an attacker test password guesses offline. With WPA2-Personal a recorded four-way handshake can be attacked offline with a dictionary. A long, random passphrase, or WPA3 with SAE, defeats that.
Sources: NIST glossary: pre-shared key; NIST SP 800-97, Establishing Wireless Robust Security Networks: A Guide to IEEE 802.11i; Wi-Fi Alliance: Security. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.