8 research outputs found
Efficient Attribute-Based Smart Contract Access Control Enhanced by Reputation Assessment
Blockchain's immutability can resist unauthorized changes of ledgers, thus it
can be used as a trust enhancement mechanism to a shared system. Indeed,
blockchain has been considered to solve the security and privacy issues of the
Internet of Things (IoT). In this regard, most researches currently focus on
the realization of various access control models and architectures, and are
working towards making full use of the blockchain to secure IoT systems. It is
worth noting that there has been an increasingly heavy pressure on the
blockchain storage caused by dealing with massive IoT data and handling
malicious access behaviors in the system, and not many countermeasures have
been seen to curb the increase. However, this problem has not been paid enough
attention. In this paper, we implement an attribute-based access control scheme
using smart contracts in Quorum blockchain. It provides basic access control
functions and conserves storage by reducing the number of smart contracts. In
addition, a reputation-based technique is introduced to cope with malicious
behaviors. Certain illegal transactions can be blocked by the credit-assessment
algorithm, which deters possibly malicious nodes and gives more chance to
well-behaved nodes. The feasibility of our proposed scheme is demonstrated by
doing experiment on a testbed and conducting a case study. Finally, the system
performance is assessed based on experimental measurement
A Survey of Asynchronous Programming Using Coroutines in the Internet of Things and Embedded Systems
Many Internet of Things and embedded projects are event-driven, and therefore
require asynchronous and concurrent programming. Current proposals for C++20
suggest that coroutines will have native language support. It is timely to
survey the current use of coroutines in embedded systems development. This
paper investigates existing research which uses or describes coroutines on
resource-constrained platforms. The existing research is analysed with regard
to: software platform, hardware platform and capacity; use cases and intended
benefits; and the application programming interface design used for coroutines.
A systematic mapping study was performed, to select studies published between
2007 and 2018 which contained original research into the application of
coroutines on resource-constrained platforms. An initial set of 566 candidate
papers were reduced to only 35 after filters were applied, revealing the
following taxonomy. The C & C++ programming languages were used by 22 studies
out of 35. As regards hardware, 16 studies used 8- or 16-bit processors while
13 used 32-bit processors. The four most common use cases were concurrency (17
papers), network communication (15), sensor readings (9) and data flow (7). The
leading intended benefits were code style and simplicity (12 papers),
scheduling (9) and efficiency (8). A wide variety of techniques have been used
to implement coroutines, including native macros, additional tool chain steps,
new language features and non-portable assembly language. We conclude that
there is widespread demand for coroutines on resource-constrained devices. Our
findings suggest that there is significant demand for a formalised, stable,
well-supported implementation of coroutines in C++, designed with consideration
of the special needs of resource-constrained devices, and further that such an
implementation would bring benefits specific to such devices.Comment: 22 pages, 8 figures, to be published in ACM Transactions on Embedded
Computing Systems (TECS