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This paper presents new speed records for 128-bit secure elliptic-curve Diffie-Hellman key-exchange software on three different popular microcontroller architectures. We consider a 255-bit curve proposed by Bernstein known as Curve25519, which has also been adopted by the IETF. We optimize the X25519 key-exchange protocol proposed by Bernstein in 2006 for(More)
By shrinking the technology and reducing the energy requirements of integrated circuits, producing ultra-low-power devices has practically become possible. Texas Instruments as a pioneer in developing FRAM-based products announced a couple of different microcontroller (MCU) families based on the low-power and fast Ferroelectric RAM technology. Such MCUs(More)
In the era of the Internet of Things, smart electronic devices facilitate processes in our everyday lives. Texas Instrument's MSP430 microcontrollers target low-power applications, among which are wireless sensor, metering and medical applications. Those domains have in common that sensitive data is processed, which calls for strong security primitives to(More)
Near field communication (NFC) is a recent popular technology that will facilitate many aspects of payments with mobile tokens. In the domain of public transportation payment systems electronic payments have many benefits, including improved throughput, new capabilities (congestion-based pricing etc.) and user convenience. A common concern when using(More)
Electronic cash is a suitable solution for payment systems, in which the user’s identity should not be revealed during the payment. This is for example the case for public transportation payment systems. One electronic cash scheme, efficient during the spending phase, was proposed by Brands’. This scheme, as all privacy-preserving payment schemes, is based(More)
Ever since its invention in the 1980s, e-cash has been considered a promising solution for privacy-preserving electronic payments. However, the computational capabilities, required for the processing of e-cash protocols, are demanding. Only recent works show the feasibility of implementing e-cash on constrained platforms. A particularly challenging, while(More)
Until recently, the desire for user privacy in intelligent transportation systems seemed to be at odds with the cost constraints of payment tokens. There is need for low-cost payment devices that can be produced in massive quantities while sophisticated cryptographic techniques seem to be too computationally intensive to be used in such devices. Our(More)
We propose a new lightweight payment scheme for transit systems called P4R: Privacy-Preserving Pre-Payments with Refunds. In P4R a user deposits money to obtain a bundle of credentials, where each credential allows to make an arbitrary ride. The actual fare of a trip is determined on-the-fly when exiting. Overpayments are refunded where all trip refunds of(More)
We propose a new lightweight cryptographic payment scheme for transit systems, called P4R (Privacy-Preserving Pre-Payments with Refunds), which is suitable for low-cost user devices with limited capabilities. Using P4R, users deposit money to obtain one-show credentials, where each credential allows the user to make an <i>arbitrary</i> ride on the system.(More)
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