A public-key infrastructure for key distribution in TinyOS based on elliptic curve cryptography

TLDR: It is demonstrated that public keys can be generated within 34 seconds, and that shared secrets can be distributed among nodes in a sensor network within the same, using just over 1 kilobyte of SRAM and 34 kilobytes of ROM.

Abstract: We present the first known implementation of elliptic curve cryptography over F/sub 2p/ for sensor networks based on the 8-bit, 7.3828-MHz MICA2 mote. Through instrumentation of UC Berkeley's TinySec module, we argue that, although secret-key cryptography has been tractable in this domain for some time, there has remained a need for an efficient, secure mechanism for distribution of secret keys among nodes. Although public-key infrastructure has been thought impractical, we argue, through analysis of our own implementation for TinyOS of multiplication of points on elliptic curves, that public-key infrastructure is, in fact, viable for TinySec keys' distribution, even on the MICA2. We demonstrate that public keys can be generated within 34 seconds, and that shared secrets can be distributed among nodes in a sensor network within the same, using just over 1 kilobyte of SRAM and 34 kilobytes of ROM.

Figures

TABLE VI MEMORY OVERHEAD OF MODULAR EXPONENTIATION, DETERMINED

Fig. 3. Time required to compute 2x (mod p), where p is prime, on the MICA2.

TABLE VII ENERGY CONSUMPTION OF MODULAR EXPONENTIATION, DETERMINED

Fig. 4. Typical exchange of a shared secret under Diffie-Hellman based on ECDLP.

Fig. 5. Running time for EccM 1.0, a TinyOS module which selected for a node at random, using a polynomial basis over F2p , a curve, a point, and a private key, thereafter computing the node’s public key. Points are labelled with running times. For larger keys (e.g., 63-bit), the module failed to produce results.

Fig. 6. Primary memory used by EccM 1.0, a TinyOS module which, using a polynomial basis over F2p , selected for a node at random a curve, a point, and a private key, thereafter computing the node’s public key. Although the sizes of the .bss and .data segments are fixed during execution, stack is defined here as the maximum of the application’s stack size during execution. Keys of 63 bits or more exhaust the MICA2’s 4,096 B of SRAM.