Preshared keys are assigned to client devices, users, or user groups. The set of valid preshared keys or keys derived therefrom is distributed to network devices such as wireless access points. A client device attempts to establish a secure network connection with a network device using its assigned preshared key. A network device identifies the client device's preshared key by selecting a candidate key from its set of valid preshared keys. The network device determines a validation cryptographic checksum based on the selected candidate key. If the validation cryptographic checksum matches the client's cryptographic checksum, the network device establishes a secure network connection with the client device using this candidate key. If the validation cryptographic checksum does not match the cryptographic checksum provided by the client device, the network device repeats this comparison using different candidate keys selected from its set of valid preshared keys until a match is found.