through. Moreover, if the sensor detects an anomaly
such as raising temperature, it will add it directly to
the path. At the end of the supply chain, a verifier ex-
tracts the trace and verifies its validity, and what the
exact alerts that got generated. The verifier is often
a supply chain manager that wants to have a global
overview of its supply chain in order to mitigate any
potential threats.
In order to preserve actors’ privacy, actors’ identi-
ties have to be kept secret. Encryption is a straightfor-
ward solution preventing eavesdroppers from steal-
ing identities and impersonatingany legitimate supply
chain actor. However, any technical solution that ad-
dresses secure and privacy preserving product track-
ing should take into account the limitations of sen-
sor nodes. These are constrained devices in terms
of computation power, memory, and energy. Due to
the limited memory featured by sensors, straightfor-
ward storage of the collected encrypted steps’ identi-
ties cannot be afforded. Thus, a compression mecha-
nism to reduce the size of the path traces is a manda-
tory requirement in order to overcome the memory
limitation of sensors. Also, the scarce energy re-
sources of sensor nodes, make the implementation of
complex functions such as public key encryption al-
gorithms difficult (Gennaro et al., 1997). Therefore,
our solution places all the complex computations on
the supply chain actor’s system in order to suit the
scarcity of the computational resources.
The main features of the suggested tracking
scheme are as follows:
• It allows the supply chain manager to verify the
legitimacy of the path taken by a product. More
precisely, it allows the supply chain manager to
verify which set of actors, a product has visited.
• It tracks all the anomalies that got raised by the
sensor nodes along the supply chain. For each
anomaly, our solution links it to the correspond-
ing supply chain actor.
• It guarantees the privacy of products and there-
with actors in the supply chain. Only the supply
chain manager is able to verify the path taken by
a product.
Moreover the scheme is suitable for low capacity
sensors. It only requires a few Kbytes storage. The
protocol execution for each supply chain step requires
only two modular multiplication.
1.1 Scenario: Importation of Chemicals
from China to Europe
Figure 1 illustrates typical supply chain example from
RESCUEIT project (Gomez et al., 2011). Aerosols
are imported from a Chinese harbour toward the har-
bour of Le Havre, in France. Shipped goods are
household and gardening chemicals: Garlon brush
cluttering 350 ml, DECAP four express 500 ml
and Ronstar 2kg. These products are meant to be
shipped by boat from a Chinese harbour. When re-
ceived at the Le Havre harbour, the merchandise is
checked by customs against REACH (Williams et al.,
2009)regulations. REACH is the European Commu-
nity Regulation on chemicals and their safe use (EC
1907/2006) (Williams et al., 2009). It deals with the
registration, evaluation, authorization and restriction
of chemical substances. The aim of REACH is to
provide an additional layer of protection for humans
and the environment through the better and earlier
identification of the intrinsic properties of chemical
substances. To that extend, REACH introduces spe-
cific constraints on chemicals along the supply chain.
They include the flash point, incompatibilities be-
tween products, and humidity conditions for chemi-
cals. At the Le Havre harbour, french customs with
the support of a Approved Economic Operator pro-
ceed to a merchandise integrity check. After a check
of administrative document describing the content of
the cargo, customs verify the quantity and quality of
the goods received. Once quality checks have been
performed at Le Havre harbour, and customs have
verified that the merchandise is compliant with safety
regulations, products are shipped by pickup trucks to-
ward the warehouse located close to Savigny le Tem-
ple. This warehouse belonging to K+N (Khune and
Nagel, 2013) is classified SEVESO II. This classifi-
cation defines a set of safety management systems,
emergency and land-use planning. In addition, it re-
inforces provisions on inspections to be carried out
by classified sites. In this case specific safety mea-
sures are implemented on site, such as storage rules
(e.g. limited quantity of chemical stored at the same
place). Finally, household and gardening products are
distributed by retailers (e.g. supermarket) such as the
Casino group (Casino, 2013).
In case of anomalies along the supply chain such
as temperature raising, the impact on population
safety, and on the environment can be disastrous. For
instance, an explosion might take place at the ship-
ment process, which depending on its intensity, fire
can have more or less serious impact on individual
health (e.g., slightly burning to death). Therefore,
anomalies detection mechanism should be in place to
mitigate potential accidents.
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