Blinded Diffie-Hellman: Preventing eavesdroppers from tracking payments

Abstract

In this paper we present a novel form of ECC Diffie-Hellman key agreement that provides privacy and anti-tracking for contactless payments. The payer's device can be authenticated by a payment terminal using a static public key with associated certificates belonging to the payer's device; however, a pas- sive eavesdropper is unable to determine the static data and keys that might otherwise be used to identify and track the payer. The new protocol has better performance than alternative protocols; it avoids the payer's device having to support signature algorithms with dedicated hashes and it has a security proof given in [3]. The new protocol does not appear in any standards known to the authors.