The Pre-Shared Key(PSK) is a password method that works with a symmetric encryption key. Among other things, Pre-Shared Key is used in WiFi Protected Architecture(WPA) and in WLANs that operate without radius servers, which is the case in small WLANs or in home networks.
With the pre-shared key, the user must enter a passphrase, a letter- digit-character creation that can be between 8 and 64 letters and digits long. Inconjunction with the service set identification( SSID), the access point( AP) calculates the master secret from this using a hash function. From this master secret, an individual key for the Temporal Key Integrity Protocol ( TKIP) is obtained via nonces (number used once) - i.e., sequences of letters and digits used once.
In order to better control and restrict the access and access rights of individual devices, the private pre-shared key( PPSK) is an access method that assigns an individual network key to each individual device, for example in the Internet of Things( IoT).