IEEE Consumer Electronics Magazine - March/April 2020 - 14

Privacy and Security by Design

Table 1. PUFchain case study platform.
PUFchain parameters
IoT Devices

Specific values
Trusted
node

Client node

Raspberry
Pi 3

Model B+

Model B,
Raspberry
Pi 1

Operating system
Communication

Figure 8. Working principle of the PUF.

circuits are compared with each other to generate cryptographic keys.

Figures-of-Merit (FOMS) of PUF
A set of properties including uniqueness, reliability, and randomness, has to be satisfied by
the CRPs before they can be used for applications.12 Uniqueness is the property to evaluate
the uniqueness of the keys generated by the PUF
design. A key once generated by a PUF design
has to be unique to the respective module. Once
the key is generated, the PUF module has to be
reliable and should have the capability of generating the same key under various conditions
such as power supply variations or aging effects.
Both uniqueness and reliability are evaluated by
checking the Hamming distance between the
keys generated. Randomness is another key
FoM. Once the key is generated, there has to be
an equal number of 0s and 1s in it.

SPECIFIC CASE STUDY OF PUFCHAIN
Pufchain Security Verification
The PUFChain methodology is written in the
Scyther simulation environment using the Security Protocol Description Language (.spdl).21 The
simulation is conducted in Scyther v1.1.3 in the
Ubuntu 18.04.3 OS. According to the features of
Scyther, we define the role of D and S, where S is
the source of the block and D is the miner or
authenticator node in the network. In the simulation, we have initialized all the features, as
described in the model description. PUF random
numbers are chosen randomly in this

Raspbian 4.14
Wireless

Wired and
wireless

PUF and hashing
module

AlteraÒ DE-2

Transaction
completion time

192.3 ms

simulation. In our simulation, we have evaluated
the scenario at the authenticated node (D) to
find whether it authenticated the blocks thoroughly without any compromise.

Real-Life Testbed of PUFchain
The Node-RED development tool was used
for designing the trusted node and the client
nodes. The environment is more suited for development of IoT applications on multiple platforms, and hence, there is also a possibility of
portability. The experimental setup consists of
the Raspberry Pi single board computers and an
Ò
Altera DE2 FPGA module on which the PUF and
the hashing module were developed. The characterization of the PUFchain is listed in Table 1.
For evaluation of PoP and PUFChain, they were
implemented on a testbed containing six Raspberry Pi single board computers of which one
was a trusted node. For evaluating the performance across high performance and low performance devices, the nodes in the network are a
combination of Raspberry Pi 1, Raspberry Pi 3
Model B, and Raspberry Pi 3 Model B+ boards.
The prototype of PUFchain is shown in Figure 9.
Transaction Time Analysis of PUFchain
As listed in Table 1, the total time taken to
complete a transaction is 192.3 ms. Table 2
presents the time taken by various devices to
add the block that the device has received.

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IEEE Consumer Electronics Magazine - March/April 2020

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