PINkoodide

PINkoodide, or PIN codes, are numeric personal identifiers used to verify a person’s identity during access to systems or services. They are widely used with payment cards (ATMs and point-of-sale terminals), mobile devices (SIM and screen locks), and smart cards. PINs are designed to be known only to the user and not transmitted in clear form.

Typical formats: four digits dominate globally, though many systems allow six digits or longer. In card payments, the PIN is entered on a keypad and validated by the issuing bank or by the card’s secure element. In many cases the PIN is not stored as plain text; instead a verifier value or encrypted representation is used, and attempts are limited to prevent brute-force guessing. Some devices use additional verification methods, such as card-based verification methods (CVM) or PVV in card networks.

Security considerations: PIN disclosure can occur through shoulder surfing or smudge attacks. If a PIN is compromised, or the device is lost, the user should contact the issuer and possibly suspend services. Reuse of a PIN across accounts increases risk. Many systems implement lockouts after a number of failed attempts. Use of two-factor authentication where possible improves security. Best practices include choosing a non-obvious, unique PIN, covering the keypad when entering, and not writing it down where others can find it. Regular changes are advised in some contexts, though not universally recommended for all cards.

Alternatives and context: PINs are commonly compared with passwords and can be combined with biometrics or hardware tokens in multi-factor authentication. In financial and security standards, PIN management is part of broader authentication and encryption practices, with organizations auditing PIN handling under information security frameworks.