A verifier is satisfied with the claimed online identity if shown an expected fixed identifier (password, PIN, key).
The prover's sphere
The verifier's sphere
The fixed identifier can be compromised at:
Special concern for multi-use fixed identifier: when used for several verifiers. A compromised single
verifier will compromise all.
Explicit Identifiers are categorized as:
Modifiable identifiers allow for quick recovery of a compromised id, while non-modifiable give the hackers a permanent advantage.
Non modifiable identifiers are divided to common social parameters (e.g. mother maiden name, social security number), and to biometric identifiers (fingerprint, iris, palm, DNA).