if (!Win32.CryptAcquireContextW(
  out prov,
  container_name,
  null,
  PROV_GOST_2001_DH,
  CRYPT_NEWKEYSET | CRYPT_SILENT))
  {
    ThrowLastError();
  }

if (!Win32.CryptSetProvParam(prov, PP_KEYEXCHANGE_PIN,
    Encoding.UTF8.GetBytes(pin), 0))
    {
      ThrowLastError();
    }

if (!Win32.CryptGenKey(prov, AT_KEYEXCHANGE, 0, ref key))
  {
    ThrowLastError();
  }
            
x.ProviderType = 75;
x.ProviderName = "Crypto-Pro GOST R 34.10-2001 Cryptographic Service Provider";
var req = x.createPKCS10(strDN, "1.3.6.1.4.1.311.2.1.21");
if (!Win32.CryptReleaseContext(prov, 0))
  {
    ThrowLastError();
  }