ecdhe + ec_key_check_key microbenchmark

ecdh_microbenchmark.c

#include <openssl/opensslv.h>
#include <openssl/ecdh.h>
#include <openssl/evp.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/utsname.h>
#include <time.h>

struct curve_testcase
{
     int nid;
     const char *name;
};

const struct curve_testcase testcases[] = {
     { .nid = NID_X9_62_prime256v1, .name = "secp256r1" },
     { .nid = NID_secp384r1, .name = "secp384r1" },
     { .nid = NID_secp521r1, .name = "secp521r1" },
     // too lazy to write the conditional to support the keygen implementation for this curve.
     //{ .nid = NID_X25519, .name = "x25519" },
};

const int NUM_ITERS=10000;
const unsigned int USECS_IN_SEC=1000000;


static void print_summary(const struct curve_testcase *testcase, double avg_usecs_keygen, double avg_usecs_key_check)
{
     printf("%s: %f avg usecs for ECDH key generation %f avg usecs for EC_KEY_check_key in %d iterations \n", testcase->name, avg_usecs_keygen, avg_usecs_key_check, NUM_ITERS);
}

static void microbenchmark_ec_key_check_key(const struct curve_testcase *testcase)
{
     double usecs_elapsed_keygen = 0;
     double usecs_elapsed_key_check = 0;
     for (int i = 0; i < NUM_ITERS; i++) {
        // Benchmark the ephemeral key generation for the curve
        double begin = clock();
        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL);
        EVP_PKEY_paramgen_init(pctx);
        EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, testcase->nid);
        EVP_PKEY *params = NULL;
        EVP_PKEY_paramgen(pctx, &params);
        EVP_PKEY_CTX *kctx = EVP_PKEY_CTX_new(params, NULL);
        EVP_PKEY_keygen_init(kctx);
        EVP_PKEY *pkey = NULL;
        EVP_PKEY_keygen(kctx, &pkey);
        EC_KEY *ec_key = EVP_PKEY_get1_EC_KEY(pkey);
        double end = clock();
        usecs_elapsed_keygen += ((end - begin) / CLOCKS_PER_SEC) * USECS_IN_SEC;

        // Benchmark key check for the curve.
        begin = clock();
        const int rc = EC_KEY_check_key(ec_key);
        end = clock();
        usecs_elapsed_key_check += ((end - begin) / CLOCKS_PER_SEC) * USECS_IN_SEC;

        EVP_PKEY_free(params);
        EVP_PKEY_CTX_free(kctx);
        EVP_PKEY_free(pkey);
    }
    print_summary(testcase, (double) usecs_elapsed_keygen / (double) NUM_ITERS, (double) usecs_elapsed_key_check / (double)
NUM_ITERS);
}


int main(void)
{
    struct utsname name;
    uname(&name);
    printf("starting ECC microbenchmark. Platform: %s %s, Openssl version: %s\n",
            name.sysname,
            name.machine,
            OPENSSL_VERSION_TEXT);

     for (int i = 0; i < (sizeof(testcases) / sizeof(testcases[0])) ;
i++) {
         microbenchmark_ec_key_check_key(&testcases[i]);
     }
}

Note: EC_KEY_check_key validation check is unnecessary for Curve x25519, so the line 20-21 can be safely removed.