APDU Simulator

Overview

The APDU Simulator emulates a smart card endpoint that responds to ISO 7816-4 APDU commands. It can either drive a connected reader (PC/SC, NFC) using a virtual or real card, or run in pure mock mode for offline development.

Quick Start

1. Open the APDU Simulator — From the home screen, choose Simulator → APDU Simulator.
2. Pick a card type — Select EMV Contact, EMV Contactless, or MIFARE in the Card Session tab.
3. Choose an interface — Select PC/SC, NFC, or Mock/USB depending on your hardware (or no hardware).
4. Set the AID — Enter the application identifier (e.g. A0000000031010 for Visa Credit, A0000000041010 for MasterCard).
5. Start the session — Click Start. The simulator will perform SELECT AID and wait for further commands.
6. Send commands or watch traffic — Use the APDU Monitor tab to send manual commands, or let the connected terminal drive the flow.

Supported Card Types

Card Session Tab

The Card Session tab is the control surface for opening, configuring, and ending a smart card session.

Configuration

• Card Type — EMV Contact, EMV Contactless, or MIFARE.
• Interface — PC/SC, NFC, or Mock/USB.
• AID — Application Identifier to select on session start.
• ATR — Static or dynamic ATR returned to the reader on power-up.
• Reader Name — The PC/SC reader to use when multiple are connected.

Session Controls

• Start — Powers the virtual card and waits for APDUs.
• Reset — Re-issues an ATR and clears session state.
• Stop — Closes the session.

Live Statistics

While the session is active, the panel displays:

• Total APDU exchanges
• Average processing time per command (ms)
• Distribution of status words returned
• Last error / exception

APDU Monitor Tab

The APDU Monitor displays every command exchange as a row showing the request, the response, and timing.

Sending Manual Commands

Use the command builder to construct an APDU:

CLA: 00     INS: A4     P1: 04     P2: 00
Lc:  07     Data: A0 00 00 00 03 10 10
Le:  00

This issues a SELECT AID for Visa Credit. The response is decoded into:

• SW1 SW2 — Two-byte status word.
• Response Data — Optional FCI template for SELECT, parsed via the TLV parser.
• Timing — Processing time in milliseconds.

Error Injection

Force the simulator to return specific error status words to test terminal error handling:

• 6982 — Security status not satisfied
• 6985 — Conditions of use not satisfied
• 6A82 — File not found
• 6A86 — Incorrect P1 P2
• 6300 — Authentication failed (with retry counter)

TLV Parser Tab

Parse BER-TLV and EMV-TLV encoded data. Paste any hex blob (FCI template, AFL, response data) and the parser will recursively expand nested tags.

Example

Input:

6F 1A 84 07 A0 00 00 00 03 10 10
A5 0F 50 0A 56 49 53 41 20 43 52 45 44 49 54
9F 38 03 9F 33 02

Output (annotated):

6F (FCI Template) [26 bytes]
└ 84 (DF Name)            A0 00 00 00 03 10 10
└ A5 (FCI Proprietary)
   └ 50 (Application Label)  "VISA CREDIT"
   └ 9F 38 (PDOL)             9F 33 02

Flow Analysis Tab

The Flow Analysis tab groups APDU exchanges into EMV transaction phases for at-a-glance review.

Phases Tracked

1. Selection — PSE / PPSE selection, AID selection, FCI return.
2. GPO — GET PROCESSING OPTIONS with PDOL data, AIP / AFL response.
3. Read Records — Each READ RECORD call iterating through the AFL.
4. Offline Authentication — SDA / DDA / CDA verification calls.
5. Cardholder Verification — VERIFY commands (online / offline PIN, signature).
6. Transaction — GENERATE AC first generate, optional second generate, AAC / TC / ARQC.
7. Script Processing — Issuer scripts after online authorization.

Each phase row shows the number of APDUs, the cumulative time, and the resulting status. Click into any phase to drill down to individual APDU exchanges.

Reader Interfaces

Response Modes

Choose how the simulator answers incoming APDUs:

• Automatic — Returns canned responses from the active EMV profile (typical for a Visa or MasterCard card).
• Manual — Pauses on each request and lets you craft the response by hand. Useful for reproducing edge cases.
• Script-based — Loads a script defining responses for a sequence of APDUs. Replays them in order regardless of input variation.

Common Status Words

Tips & Troubleshooting

• Reader not detected — Check that the PC/SC service is running and the reader is exclusively held by ISO8583Studio (close other smartcard apps).
• ATR mismatch — Some terminals validate the ATR against a list. Override the simulator’s ATR to match your expected card profile.
• Slow contactless — Reduce the response delay in mock mode; contactless kernels often time out at ~500 ms.
• TLV parse errors — Verify the input is valid hex (no 0x prefix, no commas) and that nested templates are length-correct.