SPECIFICATIONS

SPECIFICATIONS

TO FIND and download YOUR SPECIFICATION GUIDEs
to IMPLEMENT EASILY the NEXO STANDARDS
download the guides below

NEXO RETAILER SPECIFICATIONS

Allowing to Isolate the payments application to the point of sale business application

The nexo Retailer Protocol defines a set of interfaces between a card payment application and a retail point of sale system.
It offers new innovative features such as a clear separation between sale and payment, the provision of a complete series of payment and loyalty services as well as a common approach for all types of architectures and environments.

 

SCOPE

This specification contains the protocol specifications between a sale system and a payment system.
The protocol allows a sale system to request a payment system to process the payment associated to the purchase of goods or services made by a customer (cardholder).

Presents the detailed specifications of the protocol on several aspects:

  • The modelisation of the various architectures that could be supported by the protocol.
  • The way to use the transport protocol located below the application protocol that is specified.
  • The management of the messages, including the dynamic behaviour of the protocol with the error management.
  • The specification of the services offered by the protocol, and the specification of how to use these services, by the exchange of sequence of messages.
  • The static part of the protocol, definition of the messages and their components.

The information is presented into four main parts:

  • Modelling,
  • Communication level management,
  • Application protocol,
  • Definition of messages

 

DOWNLOAD

The specifications are available for free under an End-user License Agreement (EULA).
This material is part of the nexo Retailer Protocol series of specifications.

The .zip file also contains the related XML Schema and ASN.1 definitions as well as some examples of XML-coded messages.

 

nexo Acquirer specifications

The very first series of ISO 20022 card payment standards to be used between an Acceptor and an Acquirer for card-initiated payment transactions.

The nexo Acquirer protocol is based on a set of Acceptor to Acquirer Message definitions, including Authorisation, Completion, Cancellation, Reconciliation, Batch Transfer, and Diagnostic messages.The inherent flexibility of the ISO 20022 standards, and its availability to all for free, makes it stand out from other standards.

The design allows interoperability between different implementations and expansion to support value added services.The Acquirer standard allows the use of real time or batch submission as well as supporting direct connections from merchant to acquirer or via a Payment Service Provider (PSP) intermediary.

Messages are made up of a header, body and a trailer. The fact that security has been designed from the start of the development into the protocol itself is a major advantage compared toexisting standards.This allows the authentication of the initiator and the protection of the content of part or all of the body against any unauthorised alteration or capture of the transaction message.

 

SCOPE

List of the financial functions (services) managed with nexo acquirer protocol
  • Payment
  • Refund
  • Cancellation
  • Payment with Increased Amoun
  • Payment with Cashback
  • Deferred Payment
  • Voice Authorisation (referral)
  • Pre-Authorisation Services
  • Cash Advance
  • DCC
  • No show
  • Instalment Payment
  • Recurring Payment
  • Payment with Deferred Authorisation
  • Payment with Purchasing or Corporate Card Data
  • Payment with Aggregated Amount
  • Quasi-cash Payment
  • Original Credit
  • Prepaid Card Loading / Unloading
  • Card Validity Check
  • Balance Inquiry
  • Card Funds Transfer
  • MOTO

 

BENEFITS

Benefits for Acceptors

Universal ISO-based standard

Non-proprietary common protocol

Multiple-acquiring support and enforcement

Cross-border compliance

Benefits for Acquirers

Universal ISO-based standard

Multiple-acquiring offer to major cross-border retailers (e.g. multi-national companies)

Intermediary Agent to Acquirer support

 

DOWNLOAD

The latest version of specifications can be downloaded free of charge from the official ISO 20022 web site:
nexo Acquirer Protocol Specifications - Card Payment Exchanges - Acceptor to Acquirer messages V4.0

Former versions of Card Payments Exchanges - Acceptor to Acquirer messages can be obtained from the following ISO 20022 Archive location:
Card Payments ExchangesAcceptor to Acquirer messages v3.0

 

nexo Acquirer Message Usage Guide

This document contains the implementation specifications for the ISO 20022 Card Payments Exchanges messages - Acceptor to Acquirer protocol.
The following nexo Acquirer Protocol Message Usage Guide is available for free under an End-user License Agreement (EULA).

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nexo Acquirer MUG(V2 - Card Payments Exchanges messages v2.0) nexo Acquirer MUG(V2 - Card Payments Exchanges messages v2.0)

 

NEXO ATM SPECIFICATIONS

nexo-IFX ATM Protocol defines a set of ISO 20022 Message Definitions.
These messages are specifically designed to support the withdrawal of cash at an ATM location, the management of an ATM,
the security associated to the exchanges of messages at application level and the possibility to reject a transaction, if relevant.

 

SCOPE

The specification is the first part of the ISO 20022 Message Definition Report that describes the Business Transactions and underlying message set.
For the sake of completeness, the document also describes Business Activities that are not in the scope of the project.

The documentation sets:
The Business Process scope (business processes addressed or impacted by the project)
The Business Roles involved in these Business Processes

The main objectives are:

  • To explain what Business Processes and Business Activities these candidate Message Definitions have addressed
  • To give a high level description of Business Processes and the associated Business Roles
  • To document the Business Transactions and their Participants (sequence diagrams)
  • To list the candidate Message Definitions

 

DOWNLOAD

The specifications can be downloaded free of charge from the official ISO 20022 Web site

NEXO CARD PAYMENT SECURITY SPECIFICATIONS

A standardize approach with embeded security in the protocols

The “Card Payment Protocols Security” contains the specifications of the security mechanisms to secure the following nexo protocol messages:
  • nexo Acquirer protocol (ISO 20022 CAPE messages – ‘caaa’)
  • nexo TMS protocol (ISO 20022 CAPE messages – ‘catm’)
  • nexo Retailer protocol (Sale to POI protocol)
Protection of Messages

Card payments messages of the nexo protocols use four types of protection:

  1. Protection of the PIN, performed by the application.
  2. Protection of sensitive data (e.g. card data), performed by either the payment application or the nexo protocol when configured to do so.
  3. Protection of the message by a MAC (Message Authentication Code).
  4. Protection of the message by a digital signature.All the protected data and the related information are formatted according to the generic format defined by the Cryptographic Message Syntax (CMS) standard defined in the RFC 5652.

 

DOWNLOAD

This document contains the implementation of the security specifications for both the ISO 20022 Acceptor to Acquirer Card Transactions standards (nexo Acquirer and TMS protocols) and the nexo Retailer Protocol.
This material is to be used as a complementary material to the ISO 20022 Card Payment Exchanges (CAPE) specifications which are available from the official ISO 20022 Web site.
The present material is available for free under an End-user License Agreement (EULA).

nexo Card Payment Protocols Security(V1)
nexo Card Payment Protocols Security(V1)

NEXO-FAST SPECIFICATIONS

nexo-FAST describes a financial application on the Point of Interaction (POI) terminal, based on EMV chip and PIN technology. Provide specifications on a terminal transaction flow for the terminal-to-card interface, the terminal-to-cardholder interface and the exception handling. It also defines the functionalities and identifies the minimum requirements to be supported for: Payment Service (attended and unattended), Refund Service, Cancellation Service, Pre-Authorization Services, Cash Advance and Deferred Payment. 

 

nexo-FAST specifications would allow to access:

The detailed technical specification of the functions, the processing steps and the display of messages and receipts needed to perform Card Services.

Top-level flows describing each of the Card Services and, detailed flows describing the functions and processing steps needed to process the Card Services.

The Data Dictionary providing the technical description of the data elements used in the technical specification.

 

Business Considerations

nexo-FAST is based on EMV Chip and PIN technology and describes unambiguously the financial application on a terminal which meets the functional requirements in the SEPA Cards Standardisation Volume Book of Requirements. nexo-FAST has been developed with the objective of:

  • Supporting a uniform "look and feel" of transactions from the cardholder’s perspective
  • Reducing the risks of interoperability obstacles between applications
  • Enabling an open market for EMV-based components
  • Serving as the basis for a "one-stop shopping" for terminal testing and mutual recognition of type approval
  • Describing unambiguously the financial application on the SCF compliant terminal

 

The benefits of adopting nexo-FAST

EMV compliancy: a terminal running the application specifications will be able to accept all payment cards, provided they are compliant with EMV specifications.

Protocol agnostic: the specifications has been designed in a way it could work with different acquirer, TMS or retailer protocols. It can therefore easily be integrated with any of those protocols, so as to match market needs.

Multi-acquirer: specifications has been designed since its inception as a multi-acquirer payment application.

Security: the specifications are based on state-of-the-art security. A strong emphasis has been made on how the terminal data are stored and accessed, to ensure that each module within the application can only access the data that are strictly necessary to its task.

 

Overall, implementing nexo-FAST will reduce development and certification costs for terminal manufacturers, merchants and banks.

 

nexo FAST consists of:

The detailed technical specification of the functions, processing steps, display messages and receipts needed to perform Card Services

Top-level flows describing each of the Card Services and detailed flows describing the functions and processing steps needed to process the Card Services

The Data Dictionary giving the technical description of the data elements used in the technical specification

 

 nexo FAST will be delivered in two parts:

Part 1, for the POS Environment
Part 2, for the ATM

 

nexo FAST Part 1: Version 3.1

Version 3.1 of nexo FAST Part 1 is an update of Version 3.0 with clarifications and corrections responding to comments received from implementers.

The following topics are still under discussion and will be covered by bulletins during the consultation phase:

  • Dynamic Currency Conversion (DCC)
  • PIN Bypass
  • Volume Compliance of the Pre-Authorisation Services
  • Restart of Contactless kernels in Technology Selection
  • UI Request Processing

 

DOWNLOAD

nexo FAST Part 1Version 3.1
nexo FAST Part 1Version 3.1

 

NEXO IMPLEMENTATIONS

nexo Implementation Specification is based on the nexo-FAST POS payment application and the nexo protocolS. It defines in detail the structure and functions of the Host Acquirer Protocol (HAP), which is needed for the interaction of the nexo-FAST application with the nexo protocolS within the framework of a nexo implementation project.

 

The aim of this specification

To define in detail the structure and the functions of the host acquirer protocol (HAP) application with detailed descriptions of the messages and data elements when the nexo-FAST application has to interact with the nexo protocol within the framework of the an implementation project,

To define an interface application for the terminal management system with detailed descriptions of the messages and data elements used for configuration and maintenance purposes.

The interaction between the sale system and the dedicated interface (SCAP) using the nexo Retailer protocol.

 

nexo implementation project

An implementation infrastructure is made up of a standalone or integrated payment system communicating with one or several Acquirer host(s) to process a card payment transaction, a Terminal Management System host for terminal management functions, e.g. parameter download and a sales system.

 

A nexo POI terminal

A nexo POI terminal has to support: 

  • A nexo-FAST payment application.
  • A nexo Acquirer protocol application.
  • An interface to the Host Acquirer Protocol responsible for handling the nexo Acquirer protocol and the nexo TMS protocol.

Connections to at least one acquirer host in the operational environment. However the POI shall support a multi-acquirer environment. The multi-acquirer functionality is in scope of the nexo implementation  test requirements.

Connection to one TMS host for at least the purpose of parameters download.

Optionally, an interface to the sales system responsible for handling the nexo retailer protocol.

 

Participation requirements

An acquirer participating in an implementation project has to support a nexo Acquirer protocol application and optionally, a TMS protocol application if the acquirer is also the terminal manager.

A Terminal Manager participating in an implementation project has to support a TMS protocol application.

 

Download

The latest version of Integration Specifications is Version 3.2

POS integration specificationfor SEPA compliant terminals
POS integration specificationfor SEPA compliant terminals

nexo ImplementationsFunctional scope
nexo ImplementationsFunctional scope

nexo ImplementationsDisplay MessageTranslation
nexo ImplementationsDisplay MessageTranslation

NEXO TMS

 The nexo TMS protocol specifications provides an interface between a Terminal Management System (TMS) and a payment system. The protocol supports the functions for configuring, managing and maintaining the application parameters, the software and the security keys of a payment system. The protocol is based on a set of Terminal Management message definitions, including status report, management plan replacement, acceptor parameters configuration and management delegation.

 

What you will get by downloading this specifications

 The main objectives are:

To explain what Business Processes and Business Activities these Message Definitions have addressed

To give a high level description of Business Processes and the associated Business Roles

To document the Business Transactions and their Participants (sequence diagrams)

To list the Message Definitions

 

This specifications sets:

The Business Process scope (business processes addressed or impacted by the project)

The Business Roles involved in these Business Processes

 

Card Payments Exchanges – Terminal Management messages

The specifications can be downloaded free of charge from the official ISO 20022 Web site.

Former versions of Card Payments Exchanges – Terminal Management messages can be obtained from the following ISO 20022 Archive location.

Card Payments Exchanges - Terminal Management messages v3.0

Card Payments Exchanges - Terminal Management messages v2.0

Card Payments Exchanges - Terminal Management messages v1.0

 

MESSAGE USER GUIDE

The message user guide describes how to use the messages of the nexo Terminal Management Protocol described in the document "Card Payment – Terminal Management, Message Definition Report" [CAPE ACQ MDR] .

This document contains the implementation specifications for the ISO 20022 Card Payments Exchanges messages – Terminal Management protocol. The following nexo TMS Message Usage Guides are available for free under an End-user License Agreement (EULA).

 

DOWNLOAD

nexo TMS MUG(V2 - Card Payments Exchanges messages v2.0)
nexo TMS MUG(V2 - Card Payments Exchanges messages v2.0)

nexo TMS MUG(V1 - Card Payments Exchanges messages v1.0)
nexo TMS MUG(V1 - Card Payments Exchanges messages v1.0)

Why nexo ?
Frédéric Mazurier
Carrefour Banque
Interview