Energy-Efficient Implementation of ECDH Key Exchange for Wireless Sensor Networks

Abstract

Abstract. Wireless Sensor Networks (WSNs) are playing a vital role in an ever-growing number of applications ranging from environmental surveillance over medical monitoring to home automation. Since WSNs are often deployed in unattended or even hostile environments, they can be subject to various malicious attacks, including the manipulation and capture of nodes. The establishment of a shared secret key between two or more individual nodes is one of the most important security services needed to guarantee the proper functioning of a sensor network. Despite some recent advances in this field, the efficient implementation of cryptographic key establishment for WSNs remains a challenge due to the resource constraints of small sensor nodes such as the MICAz mote. In this paper we present a lightweight implementation of the elliptic curve Diffie-Hellman (ECDH) key exchange for ZigBee-compliant sensor nodes equipped with an ATmega128 processor running the TinyOS operating system. Our implementation uses a 192-bit prime field specified by the NIST as underlying algebraic structure and requires only 5.20 · 10 6 clock cycles to compute a scalar multiplication if the base point is fixed and known a priori. A scalar multiplication using a random base point takes about 12.33 · 10 6 cycles. Our results show that a full ECDH key exchange between two MICAz motes consumes an energy of 57.33 mJ (including radio communication), which is significantly better than most previously reported ECDH implementations on comparable platforms.

Efficient Implementation of NIST-Compliant Elliptic Curve Cryptography for Sensor Nodes

“…Practical results, obtained on an ATmega128, demonstrate that our work exceeds the state-of-the-art in ECDH key agreement and ECDSA signature generation (resp. verification), outperforming the best implementations reported in the literature by a factor of 1.35 [20] and 2.33 [22], respectively.…”

“…All currently-existing prime-field based ECC libraries use either the hybrid multiplication technique [14] (or a variant of it [6,22,33,31,20]) or employ the Karatsuba method (e.g. NaCl [17]) for the performance-critical multi-precision multiplication and squaring.…”

“…timing and SPA attacks) is similarly important. Most of the previous ECC libraries, however, do not contain countermeasures; the only two exceptions are the work from [20] and NaCl [17]. Lederer et al [20] implemented ECDH for WSNs and protected the scalar multiplication against SPA attacks by adopting highly "regular" variants of the comb and window method, respectively.…”

“…Most of the previous ECC libraries, however, do not contain countermeasures; the only two exceptions are the work from [20] and NaCl [17]. Lederer et al [20] implemented ECDH for WSNs and protected the scalar multiplication against SPA attacks by adopting highly "regular" variants of the comb and window method, respectively. Their ECDH software uses a 192-bit prime field specified by the NIST as underlying algebraic structure and needs 5.20 · 10 6 and 12.33 · 10 6 clock cycles an ATmega128 processor to to compute a fixed-point and random-point scalar multiplication, respectively.…”

Group Signatures are Suitable for Constrained Devices

“…For the point multiplication, we extended the TinyECC library [23] to support the MNT curves. The parameters of the used curve were taken from the PBC library [25] written by B. Lynn.…”