Benchmarking key store enumeration

benchmark.cpp

#include <stdio.h>
#include <windows.h>
#include <wincrypt.h>

static void failerr(const char *funName) {
  fprintf(stderr, "%s() failed: 0x%08lX\n", funName, GetLastError());
  exit(1);
}

void enum_keys(HCRYPTPROV hprov) {
  BYTE buf[1024];  // Max key name length.
  for (DWORD first_next = CRYPT_FIRST; 1; first_next = CRYPT_NEXT) {
    DWORD buf_len = sizeof buf;
    if (!CryptGetProvParam(hprov, PP_ENUMCONTAINERS, buf, &buf_len, first_next)) {
      if (GetLastError() == ERROR_NO_MORE_ITEMS)
        break;
      else
        failerr("CryptGetProvParam");
    }
  }
}

const char *csp = MS_ENH_RSA_AES_PROV_A;
const DWORD csptype = PROV_RSA_AES;

void do_benchmark(DWORD enum_flags) {
  enum_flags |= CRYPT_VERIFYCONTEXT;
  HCRYPTPROV hprov;
  if (!CryptAcquireContext(&hprov, NULL, csp, csptype, enum_flags)) {
    failerr("CryptAcquireContext");
  }

  int K = 100;
  LARGE_INTEGER perfreq, timein, timeout;
  QueryPerformanceFrequency(&perfreq);
  QueryPerformanceCounter(&timein);
  for (int i = 0; i < K; ++i)
    enum_keys (hprov);
  QueryPerformanceCounter(&timeout);
  printf(" %f ms per pass\n", (double)(timeout.QuadPart-timein.QuadPart)/perfreq.QuadPart * 1000.0 / K);

  CryptReleaseContext(hprov, 0);
}

void main() {
  printf("--- User key store access performance test... ");
  do_benchmark(0);
  printf("--- Machine key store access performance test... ");
  do_benchmark(CRYPT_MACHINE_KEYSET);
}

Related StackOverflow question: http://stackoverflow.com/questions/32516025/slow-key-enumeration-in-a-machine-rsa-key-container