How Jitter Technology Works

[Mutt]

Jitter technology (or anti-skimming vibration technology) is a hardware and software solution used in ATMs and POS terminals to prevent the installation of physical skimmers that read data from the magnetic stripe or EMV chip of bank cards. This technology creates mechanical or electromagnetic interference, disrupting the operation of skimmers in order to protect card data, including those used in carding. For educational purposes, I will describe in detail how Jitter technology works, its technical aspects, application, effectiveness and limitations in the context of combating fraud.

1. What is Jitter technology and its purpose​

Jitter technology is a method of protecting ATMs and POS terminals from skimming, which involves creating controlled vibrations or electromagnetic oscillations in the card slot. These interferences prevent skimmers (devices installed to steal magnetic stripe or EMV chip data) from reading data correctly.

Purpose:

• Skimmer Interference: Jitter creates unstable conditions for the magnetic or NFC readers of skimmers, causing errors when reading data.
• Data Theft Prevention: Protects PAN, expiration date, CVV1 (for magnetic stripe) or EMV chip data used by carders.

In the context of carding: Jitter technology makes it difficult to obtain data to clone cards that carders are trying to use in stores without 3DS or older terminals.

2. How Jitter Technology Works​

Jitter technology creates mechanical or electromagnetic interference in the card slot, disrupting the stability of the skimmer's reading of data. Here are its basic principles and technical aspects:

a) Operating principle​

• Mechanical vibrations:
  • A device that creates microvibrations (for example, with a frequency of 10–100 Hz) is installed in the card slot of an ATM or POS terminal.
  • These vibrations change the position of the card relative to the skimmer's reading head, causing errors in decoding magnetic signals (F2F encoding for the magnetic stripe).
• Electromagnetic interference:
  • Pulses or noise are generated in the frequency range used by skimmers (e.g. for NFC skimmers operating at 13.56 MHz according to ISO/IEC 14443).
  • This prevents the skimmer from correctly reading the EMV chip or magnetic stripe data.
• Random nature of interference:
  • Jitter uses random or pseudo-random signals to prevent skimmers from adapting to a fixed interference frequency.
• Example:
  • An ATM with Jitter technology (e.g. Diebold Nixdorf Anti-Skimming Module) vibrates the card slot at 50Hz, causing the skimmer to read distorted data (e.g. 1234567890123456 becomes 12X45678Y012Z456).

b) Technical components​

• Hardware:
  • Vibration Module: An electromechanical device (such as a piezoelectric actuator) in a card slot that creates micro-vibrations.
  • Electromagnetic Generator: A device for generating high frequency interference in the NFC range (13.56 MHz) or magnetic signals (2750 Oersteds for HiCo bands).
  • Controller: A microprocessor that controls the frequency and amplitude of the noise, often integrated into the ATM (e.g. NCR SelfServ or Wincor Nixdorf).
• Software:
  • Software in the ATM or POS terminal controls the Jitter module, activating it when a card is inserted.
  • Example: An ATM activates Jitter when a sensor detects a card and deactivates it after the transaction is completed.
• Sensor:
  • Infrared or mechanical sensors detect the presence of foreign devices (skimmers) in the slot, enhancing protection.
• Power consumption:
  • Jitter modules consume minimal power (1–5 W), integrating into the ATM system without significant energy costs.

c) Work process​

1. Card Detection: A sensor in the ATM slot detects the insertion of a card.
2. Jitter Activation: The controller initiates vibrations or electromagnetic interference:
   • Mechanical vibrations (e.g. 50 Hz) shift the card by 0.1–0.5 mm.
   • Electromagnetic pulses create noise in the range of 10–100 kHz (for magnetic stripe) or 13.56 MHz (for NFC).
3. Reading violation:
   • The skimmer magnetic head cannot correctly decode F2F signals due to vibrations.
   • NFC skimmers lose synchronization with the chip due to electromagnetic noise.
4. Transaction completion: Jitter is disabled after successful reading by the ATM (the original reader is protected from interference).

• Example:
  • The carder installs the skimmer on the ATM. The Jitter module creates vibrations, and the skimmer reads the corrupted data (Track 2: 12X45678Y012Z456=2505101XX), which is useless for cloning.

d) Integration with other systems​

• Monitoring: Jitter technology works in conjunction with sensors that detect foreign devices (such as magnetic anomalies).
• Notifications: If Jitter detects a reading failure, the ATM sends a signal to the bank to check for skimmers.

3. The effectiveness of Jitter technology in combating skimming​

Against physical skimmers​

• Magnetic stripe:
  • Jitter disrupts the stability of F2F signal reading, making magnetic stripe data (Track 1, Track 2) unreadable for the skimmer.
  • Example: Skimmer reads corrupted data (1234567890123456 → 12X45678Y012Z456) which cannot be used to clone Non-VBV card.
• EMV chip (contact):
  • Vibrations interfere with proper contact between the chip and the skimmer, disrupting the transmission of APDU commands (ISO/IEC 7816).
  • Example: The skimmer cannot execute the SELECT AID command and the chip data is not read.
• EMV chip (NFC):
  • Electromagnetic interference at 13.56 MHz blocks synchronization between the NFC skimmer and the chip.
  • Example: NFC skimmer (Proxmark3) loses connection due to noise and Auto-VBV card data is not read.

4. Practical examples​

• Scenario 1: ATM Skimmer:
  • The carder installs a skimmer on the ATM to read Non-VBV cards.
  • The Jitter module creates vibrations (50Hz) and the skimmer records corrupted data (Track 2: 12X45678Y012Z456).
  • Result: Data is useless, carder cannot clone the card.
• Scenario 2: NFC skimmer in a store:
  • The carder uses Proxmark3 to read EMV chip (Auto-VBV bin) via NFC.
  • Jitter generates interference at 13.56 MHz, disrupting synchronization.
  • Result: The skimmer does not receive data, and the card remains protected.
• Scenario 3: Cloned card online:
  • The carder bypasses Jitter (e.g. by compromising the POS terminal) and obtains Non-MCSC card data.
  • Trying to use data in store but Stripe Radar triggers 3DS due to suspicious IP (GeoIP: Nigeria).
  • Result: Transaction is rejected due to missing OTP.

5. Limitations of Jitter Technology​

• Obsolete ATMs:
  • Not all ATMs are equipped with Jitter (especially in developing countries), which allows skimmers to work.
  • Example: An old ATM without Jitter allows the skimmer to read the magnetic stripe data.
• Adaptation of skimmers:
  • Modern skimmers can use filters to suppress vibrations or interference, although this requires complex engineering.
  • Example: A skimmer with active noise reduction can partially bypass Jitter.
• NFC skimmers outside the ATM:
  • Jitter only protects the card slot, while NFC skimmers can read data in a crowd (for example, via Proxmark3).
  • Solution: Banks are switching to biometrics and 3DS for security.
• Detection Delay:
  • Jitter prevents skimming, but does not always notify about the skimmer, requiring additional sensors.

6. Integration with other security measures​

• Anti-skimming sensors:
  • Infrared or magnetic sensors detect foreign devices in the slot.
  • Example: Diebold Nixdorf Anti-Skimming Module combines Jitter with sensors.
• EMV chips:
  • Dynamic cryptography (ARQC) makes chip cloning impossible even if the skimmer bypasses Jitter.
• 3D-Secure:
  • Requires OTP or biometrics for online transactions, blocking the use of skimmed data.
• Antifraud systems:
  • Stripe Radar, Adyen use GeoIP, Device Fingerprinting and behavioral analysis to detect skimmed cards.
• Monitoring:
  • Banks monitor ATM transactions to identify anomalies (such as multiple failures).

7. Conclusion​

Jitter technology works by creating mechanical vibrations or electromagnetic interference in the card slot, disrupting the skimmers that try to read the magnetic stripe or EMV chip data. It effectively prevents card data theft at ATMs and POS terminals. When combined with EMV chips, Jitter significantly reduces the effectiveness of skimming, making carding expensive and risky. The limitations (outdated ATMs, skimmer adaptation) are compensated by additional security measures such as sensors and monitoring. As a result, skimmed data becomes virtually useless for transactions in modern systems.

If you want to dive deeper into other aspects, such as how anti-skimming sensors work or how banks use HSMs to protect data, let me know!