The implementation and analysis of the ECDSA on the Motorola StarCore SC140 DSP primarily targeting portable devices

The viability of the Elliptic Curve Digital Signature Algorithm (ECDSA) on portable devices is important due to the growing wireless communications industry, which has inherent insecurities. The StarCore SC140 DSP (SC140) targets portable devices, and therefore is a prime candidate to study the viability of the ECDSA on such devices. The ECDSA was implemented on the SC140 using a Koblitz curve over GF(2163). The τ-adic representation of polynomials involved in the elliptic curve point-multiplication is exploited to achieve superior performance. The ECDSA was implemented and optimized in C and assembly, and verified in hardware. The performance of the C and assembly implementations is analyzed and compared to previously published results. The ability of the compiler to generate efficient cryptographic related code and the SC140 to perform efficient operations is discussed. Numerous compiler optimization improvements that considerably enhance the performance of the generated assembly are suggested. Coding guidelines that state simple measures to improve the performance of the implementation and help to achieve efficient C and assembly are listed. Finally, security issues, with respect to the implementation and focusing on side-channel attacks (SCA) are investigated, including estimated performance penalties due to adding resiliency. Two SCA countermeasures specific to the implementation are also described. In summary, the implemented ECDSA signature generation and verification processes require 4.43 and 8.63 ms when the SC140 operates at 300MHz. Methods of optimizing the implementation to further reduce execution times are also presented.