Computing cardinalities of Q-curve reductions over finite fields

We present a specialized point-counting algorithm for a class of elliptic curves over F\_{p^2} that includes reductions of quadratic Q-curves modulo inert primes and, more generally, any elliptic curve over F\_{p^2} with a low-degree isogeny to its Galois conjugate curve. These curves have interesting cryptographic applications. Our algorithm is a variant of the Schoof--Elkies--Atkin (SEA) algorithm, but with a new, lower-degree endomorphism in place of Frobenius. While it has the same asymptotic asymptotic complexity as SEA, our algorithm is much faster in practice.Comment: To appear in the proceedings of ANTS-XII. Added acknowledgement of Drew Sutherlan

Computation of Trusted Short Weierstrass Elliptic Curves for Cryptography

Short Weierstrass's elliptic curves with underlying hard Elliptic Curve Discrete Logarithm Problems was widely used in Cryptographic applications. This paper introduces a new security notation 'trusted security' for computation methods of elliptic curves for cryptography. Three additional "trusted security acceptance criteria" is proposed to be met by the elliptic curves aimed for cryptography. Further, two cryptographically secure elliptic curves over 256 bit and 384 bit prime fields are demonstrated which are secure from ECDLP, ECC as well as trust perspectives. The proposed elliptic curves are successfully subjected to thorough security analysis and performance evaluation with respect to key generation and signing/verification and hence, proven for their cryptographic suitability and great feasibility for acceptance by the community.Comment: CYBERNETICS AND INFORMATION TECHNOLOGIES, Volume 21, No

IMPLEMENTING ELLIPTIC CURVE CRYPTOGRAPHY ON PC AND SMART CARD

Elliptic Curve Cryptography (ECC) is a relatively new branch of public key cryptography. Its main advantage is that it can provide the same level of security as RSA with significantly shorter keys, which is beneficial for a smart card based implementation. It is also important as a possible alternative of RSA. This paper presents the author´s research concerning ECC and smart cards. The authors introduce their ECC prototype implementation that relies on Java Card technology and is capable of running on smart cards. Test results with various cards are attached. It is also analyzed in what extent algorithms with the complexity of ECC can be executed in smart card environment with limited resources