What is Jitter?
Jitter is an anti-skimming technique, which distorts the magnetic strip's readout by altering the card's speed or motion as it is swiped or pulled into a card reader or ATM. Jitter is designed to make any copied information unreadable by a card skimmer, and thus unusable.
Jitter helps fight card skimming, which is one of the ways used by criminals to get a credit or debit card number. A person can install a device that copies the information passed through the credit or debit card reader or ATM in order to copy or "skim" the amount. Instead, these numbers are used for making fraudulent purchases.
Breaking Down Jitter
Jitter technology is designed to make copying credit and debit card numbers more difficult for unauthorized card readers. A credit or debit card is most likely to be scanned in ATMs and other devices and is less likely to be a feature of machines that allow a person to swipe their own card.
Jitter itself is a stutter; that is the system does not take in the card at a steady pace when an ATM accepts the card you are inserting, and may instead stop and start the scan.
Most skimming devices require a quick swipe to skim the numbers properly. Jitter technology may not work well in machines which require a person to manually dip into a credit or debit card. Usually, this type of swipe feature is used in older ATMs, but it can also be used in more modern machines.
Jitter is not a full-scale method of fooling a skimmer with a credit card, but it can help reduce the probability of reading cards if a skimmer has been installed.