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Tone Lock: The New Security Feature Added by LISNR

While fraud during payments and authentication is more common for online transactions, concerns around man-in-the-middle and replay attacks exist for person-present proximity transactions.  These attacks are most common where QR codes are used, where taking a picture of a consumer presented QR code can result in data being compromised, unauthorized entry or fraudulent payments.

Insert LISNR Tone Lock. Built on LISNR Point 2.1, Tone Lock is designed to protect against outside devices reading sensitive data. Without an exact match of the pre-shared UUID to the UUID embedded in the signal header, the receiving device will not demodulate the transmission and no payload data will be read. 

With Tone Lock enabled, devices are designated and secured for the data transmission, avoiding man-in-the-middle attacks from other devices running the LISNR SDK and replay attacks, from transmissions being recorded and reused found within QR codes. 

The security level protection of Tone Lock is dependent on the frequency of UUID issuance from the merchant network. One-time or infrequent issuance will protect from a man in the middle attack from a fraudulent party trying to read payload data from an active transmission. Frequent UUID issuance or issuance for individual transactions will protect against man in the middle and replay attacks, where a fraudulent party records and reuses the transmission for authorization or payment.


LISNR’s proximity solutions ensure secure, seamless and contactless data transfer. Powered by a ubiquitous device & OS platform, LISNR’s non-captive near-field association provides proof-present authentication enabled through proximity tokens. From entry validation to payments and fulfillment, LISNR empowers merchant micro-moments across the customer journey. Headquartered in Cincinnati, LISNR is currently deployed in 8 countries via multiple global partners. LISNR powers transactions and connects the online to offline customer journey globally with the most advanced near Ultrasonic Data Platform. Founded in 2012, LISNR’s major investors include Visa, Intel, Jump Capital, Mercury Fund, R/GA, and Synchrony Financial. To learn more about the LISNR technology visit: or email