CWA 16926-6:2022

Extensions for Financial Services (XFS) interface specification Release 3.50 - Part 6: PIN Keypad Device Class Interface - Programmer’s Reference

Scope

This section describes the application program interface for personal identification number keypads (PIN pads) and other encryption/decryption devices. This description includes definitions of the service-specific commands that can be issued, using the WFSAsyncExecute, WFSExecute, WFSGetInfo and WFSAsyncGetInfo functions.
This section describes the general interface for the following functions:
• Administration of encryption devices
• Loading of encryption keys
• Encryption / decryption
• Entering Personal Identification Numbers (PINs)
• PIN verification
• PIN block generation (encrypted PIN)
• Clear text data handling
• Function key handling
• PIN presentation to chipcard
• Read and write safety critical Terminal Data from/to HSM
• HSM and Chipcard Authentication
• EMV 4.0 PIN blocks, EMV 4.0 public key loading, static and dynamic data verification
If the PIN pad device has local display capability, display handling should be handled using the Text Terminal Unit (TTU) interface.
The adoption of this specification does not imply the adoption of a specific security standard.
Important Notes:
• This revision of this specification does not define all key management procedures; some key management is still vendor-specific.
• Key space management is customer-specific, and is therefore handled by vendor-specific mechanisms.
• Only numeric PIN pads are handled in this specification.
This specification also supports the Hardware Security Module (HSM), which is necessary for the German ZKA Electronic Purse transactions. Furthermore, the HSM stores terminal specific data.
This data will be compared against the message data fields (Sent and Received ISO8583 messages) prior to HSM-MAC generation/verification. HSM-MACs are generated/verified only if the message fields match the data stored.
Keys used for cryptographic HSM functions are stored separate from other keys. This must be considered when importing keys.
This version of PIN pad complies to the current ZKA specification 3.0. It supports loading and unloading against card account for both card types (Type 0 and Type 1) of the ZKA electronic purse. It also covers the necessary functionality for ‘Loading against other legal tender’.
Key values are passed to the API as binary hexadecimal values. When hex values are passed to the API within strings, the hex digits 0xA to 0xF can be represented by characters in the ranges ‘a’ to ‘f’ or ‘A’ to ‘F’.
The following commands and events were initially added to support the German ZKA standard, but may also be used for other national standards:
• WFS_INF_PIN_HSM_TDATA
• WFS_CMD_PIN_HSM_SET_TDATA
• WFS_CMD_PIN_SECURE_MSG_SEND
• WFS_CMD_PIN_SECURE_MSG_RECEIVE
• WFS_CMD_PIN_GET_JOURNAL
• WFS_SRVE_PIN_OPT_REQUIRED
• WFS_CMD_PIN_HSM_INIT
• WFS_SRVE_PIN_HSM_TDATA_CHANGED