P

packet

A unit of network transmission; specifically may refer to the unit of data transmitted across a packet-switched network (such as the Internet).

packet-switching

A communication method in which data is broken into parts called packets that are transmitted over diverse routes and then reassembled upon arrival at the receiving end. It is the communication method used on the Internet.

PCT

Private Communication Technology; a protocol specification released by Microsoft in late September 1995, describing mechanisms for secure communication between individuals on the Internet, providing encryption and authentication.

PEM

Privacy Enhanced Mail; an Internet standard defining a protocol for the secure, authenticable, and nonrepudiable transmission of electronic mail.

PGP

Pretty Good Privacy; a freely distributed program implementing public key cryptography for e-mail, and also sometimes used for electronic commerce purposes.

PIN

Personal Identification Number; the number used by a cardholder to authenticate card ownership for ATM or debit card transactions. The cardholder enters his PIN into a PIN pad. The PIN is required to complete an ATM/debit card transaction.

ping

Packet Internet Groper; a simple TCP/IP network application in which the originating hosts sends a signal to a destination host to determine whether the destination host is reachable through the network.

PNREF

Payment Network Reference ID (PNREF); a unique transaction identification number. The PNREF is used to identify the transaction for billing and reporting purposes.

point of sale

The place and time at which a transaction occurs. Point of sale (POS) also refers to the devices or software used to capture transactions.

port

The entry point into a network computer.

post authorization

A transaction for which a voice authorization was received.

post-auth posting

The process of recording debits and credits to individual cardholder account balances.

PPP

Point to Point Protocol; a protocol defining the connection of a single host to another host over a bidirectional link (such as a telephone line), and connection to network resources.

Prenotification

Prior to the initiation of the first ACH entry to an ACH receiver or the ACH receiver’s account with an RDFI, an ACH originator may, at its option, deliver or send a prenotification through an ODFI to its ACH operator for transmittal to the appropriate RDFI. The prenotification shall provide notice to the RDFI that the originator intends to initiate one or more entries to that receiver’s account in accordance to the receiver’s authorization.

prior authorized sale

A transaction for which authorization was obtained at an earlier time (when a merchant has to call for authorization before services are rendered, such as a hotel reservation, auto rental, etc.).

private key

Of the two keys used for public key cryptography, the one that must be kept secret, so the owner of the key can decrypt messages encrypted with the public key.

private label card

A bank card that can be used only in a specific merchant’s store. Typically not a bankcard.

processor

A large data center that processes credit card transactions and settles funds to merchants. A processor connects to the merchant on behalf of an acquirer via a gateway or POS system to process payments electronically. Processors edit and format messages and switch to bankcard networks. They provide files for clearing and settlement and other value-added services.

protocol

A set of rules defining the behaviors of interacting systems, particularly when applied to rules for exchanging of information between networked systems.

public key

Of the two keys used for public key cryptography, the one that can be made public, so that senders can encrypt messages.

public key cryptography

The cryptographic system in which encryption is done with one key and decryption is done with another.