Projects

• TARDIS: Time and Remanence Decay in SRAM to Implement Secure Protocols on Embedded Devices without Clocks.
  The TARDIS maintain a sense of time without power and without special-purpose hardware. The TARDIS software computes the expiration state of a timer by analyzing the decay of existing on-chip SRAM memory. The TARDIS enables coarse-grained, hourglass-like timers such that cryptographic software can more deliberately decide how to throttle its response rate.
  Project webpage: TARDIS




• Ekho: Bridging the Gap Between Simulation and Reality in Tiny Energy-Harvesting Sensors.
  Ekho is hardware tool that allows system designers to record and emulate energy harvesting conditions. The tool enables mere mortals to meaningfully conduct repeatable experiments on RFID-scale devices. Ekho uses the abstraction of I-V curves---curves that describe harvesting current with respect to supply voltage---to accurately and realistically represent harvesting conditions for a wide range of harvesting technologies. Our initial FPGA-based prototype emulates I-V curves with 0.1mA accuracy, and responds in 4.4us to changes in energy conditions. Ekho has been used by analogaphobic, digitalaphillic graduate students.
  Project webpage: Ekho




• Half-Wits: Smarter Storage for Low-Power Devices
  This work analyzes the stochastic behavior of writing to embedded flash memory at voltages lower than recommended by a microcontroller's specifications to reduce energy consumption. Flash memory integrated within a microcontroller typically requires the entire chip to operate on common supply voltage almost double what the CPU portion requires. Our approach tolerates a lower supply voltage so that the CPU may operate in a more en- ergy efficient manner. Energy efficient coding algorithms then cope with flash memory that behaves unpredictably. Our software-only coding algorithms (in-place writes, multiple-place writes, RS-Berger codes) enable reliable storage at low voltages on unmodified hardware by exploiting the electrically cumulative nature of half-written data in write-once bits. For a sensor monitoring application using the MSP430, coding with in-place writes reduces the overall energy consumption by 34%. In-place writes are competitive when the time spent on computation is at least four times greater than the time spent on writes to flash memory. Our evaluation shows that tightly maintaining the digital abstraction for storage in embedded flash memory comes at a significant cost to energy consumption with minimal gain in reliability.
  Project webpage: Half-wits
  




• CCCP: Secure Remote Storage for Computational RFID tags
  Passive RFID tags harvest their operating energy from an interrogating reader, but constant energy shortfalls severely limit their computational and storage capabilities.
  We propose Cryptographic Computational Continuation Passing (CCCP), a mechanism that amplifies programmable passive RFID tags' capabilities by exploiting an often overlooked, plentiful resource: low-power radio communication. While radio communication is more energy intensive than flash memory writes in many embedded devices, we show that the reverse is true for passive RFID tags. A tag can use CCCP to checkpoint its computational state to an untrusted reader using less energy than an equivalent flash write, thereby allowing it to devote a greater share of its energy to computation




• WSN deployment in Zakynthos island
  The loggerhead sea turtle known as the Caretta-Caretta has become an endangered specie that can only be found in the Mediterranean Sea. The turtles where leading a peaceful existence in the waters and beaches of Zakynthos but the extension and growth of touristy industry has interrupted their natural rhythms: many of them disappeared and the specie is now under direct threat.

  AIT with the support of WWF Hellas will deploying in August a sensor network to monitor and protect an area close to the beach in Zakynthos from fire. WWF claims that the ashes from a possible fire will be transferred to the beach in case of a rain, and that will damage the sand quality, affecting future nesting attempts.

  
  

• Securing Hierarchal Sensor Network
  Hierarchical processing in sensor networks offers a number of operational advantages that cannot be met by flat networks of sensors with their inherent limitations on power and processing capabilities. Using hierarchical architectures and in-network processing of information the communication overhead is minimized by combining data coming from different sources - thus eliminating redundancy, minimizing the number of transmissions and eventually saving network energy.
  The focus of this project is on securing such processing hierarchies. In particular security mechanisms must be developed that need to be adaptive to changes in the roles taken by the sensors. Hence the whole process of receiving/aggregating data and disseminating commands must be secured and explain how the security protocol can support changes to the roles of sensors in the network. This is necessary since the cooperative and collaborative nature of sensor networks may necessitate the use of configuration actions that lead to energy savings. Hence the protocol must support admission of new sensors and reorganization of existing clusters.
  




• Providing Transparent Security Services to Sensor Networks
  We introduce a new approach for design and implementation of a security platform for wireless sensor networks. At the heart of this approach is a flexible and scalable post-distribution key establishment and management module which provides basic cryptographic services. This component can be easily merged with other components and used to secure different operations at different layers. We propose a new security platform based on this key management module providing various transparent security services.