SB nº AN-1 : IFSC Negotiation during Chaining (Clarification)

EMVCo BULLETINS Application Notes: Bulletin no.1, November 2001 IFSC Negotiation during Chaining - First Edition October 2001 This note applies to EMV ’96 Integrated Circuit Card Specification for Payment Systems Version 3.1.1 and EMV 2000 Integrated Circuit Card Specification for Payment Systems Version 4.0 Book 1. This note is intended to clarify expected card behaviour related to IFSC negotiation during chaining. Clarification of use of IFSC negotiation during chaining When using the T=1 protocol, the card may indicate to the terminal the size of buffer it is able to use in order to receive blocks from the terminal. Should the block to be sent to the card be larger than the indicated buffer size, the terminal must chain data sent to the card by splitting it up into smaller blocks, each having a size equal to or less than the buffer size available in the card. The buffer size is indicated to the terminal by means of the card sending an S(IFSC request) block to the terminal, which the terminal acknowledges with an S(IFSC response) block. Since the need to chain by the terminal is determined by the size of the buffer thus negotiated, it is considered to be an unnecessary complication of the T=1 protocol to allow cards to renegotiate buffer size during reception or transmission of chained blocks. Further, this type of behaviour is not encountered in cards currently in issue. Cards should not therefore send an S(IFSC request) block during chaining. Specification change notice: For clarification, in future revisions of the EMV Specifications it is intended to add a new 6th bullet as follows to the end of Book 1, section 5.2.4.4.1 - Rules for Chaining:

• During chaining, the ICC shall not attempt to negotiate a new IFSC by sending an S(IFSC request) block to the terminal. This document contains proprietary and confidential information of EMVCo LLC. Copyright © EMVCo LLC 2001