PDA (Personal Digital Assistant)
A handheld device combining computing, telephone/fax, networking features and in some cases wireless access to the internet using WAP.

Persistent URL (PURL)
An intermediary URL for a real URL. When a PURL is entered, the browser will send a page request to a PURL server which then links to the real URL of a page. Although the real URL of a web page may change, the PURL is still the same.

Personal Identification Number (PIN)
A password used for identification. The term originated within the banking industry.

PKI (Public Key Infrastructure)
A system of authenticating electronic messages by using digital signatures and digital certificates issued by certification Authorities. A PKI is necessary for secure online stores.

Platform for Privacy Preference (P3P)
A specification that allows web browsers to automatically understand privacy practices of web sites. The browsers read the policy and then transmit certain information to sites based on the users' preferences.

Porn-napping
This happens when online pornographers re-register lapsed internet domain names for publishing sexually explicit content. The pornographers then offer to sell back the address at an exorbitant price so the previous domain name owner can protect its reputation.

Private key
The private part of a two-part public key cryptography system. The private key is kept secret and is never transmitted over a network.

Public key
The published part of a two-part public key cryptography system. Only the owner knows the private part or key.

Public key pair
Two large prime numbers called the public key and the private key. These numbers are related to each other mathematically. It is computationally infeasible to determine the private key value by only knowing the public key value.

Purchased Payment Facility (PPF)
Defined in the Online Payment Systems (Regulation) Act 1998 (Cth) as a financial product that stores value. For example, Smart Cards and other Stored Value Cards.