Distribution of elliptic twins over fixed finite fields: Numerical results

We report numerical results, and describe plans for future experiments, related to the number of prime-order curves and "elliptic twin" curves over the primes P-224, P-256, and P-384 standardized by NIST for cryptographic applications. Although these results are not sufficient to confirm the formula of Shparlinski and Sutantyo 2014 over these fields, they strongly suggest (~99% probability) that the NIST curve P-384 was not chosen from a uniform distribution over prime-order curves.