Speedpass was a keychain radio-frequency identification (RFID) device introduced in 1997 by Mobil (which merged with Exxon to become ExxonMobil in 1999) for electronic payment.

The ExxonMobil Speedpass used a cryptographically-enabled tag with a Digital Signature Transponder (DST) which incorporated a weak, proprietary encryption scheme to perform a challenge–response protocol.

On January 29, 2005, RSA Security and a group of students from Johns Hopkins University broke the proprietary encryption algorithm used by the Exxon-Mobil Speedpass.

In an attempt to prevent fraud, Speedpass users ultimately were required to enter their zip code into scanners at some gas stations.

Additionally, the New England grocery chain Stop & Shop tested Speedpass at their Boston area stores; the units were removed in early 2005.