-- class GostR3410_2001
  private byte[] signHash(byte[] hash, int hCryptProv, final int hCryptKey)
      throws SignatureException {
    // Acquire a hash object handle.
    final int hashHandle = Advapi.cryptCreateHash(hCryptProv, digestAlgId);
    if (hashHandle == 0)
      throw new SignatureException("Error acquiring digest handle. Error code: " + Win32Api.getLastError());

    try {
      // Set hash value in the hash object
      if (!Advapi.cryptSetHashParam(hashHandle, HP_HASHVAL, hash, 0))
        throw new SignatureException("Error initializing hash value. Error code: " + Win32Api.getLastError());

      // Determine key spec.
      int dwKeySpec = AT_SIGNATURE;

      final int dwAlgId = Win32Api.byteArrayToInt(Advapi.cryptGetKeyParam(hCryptKey, KP_ALGID));
      if (dwAlgId == 0)
        throw new SignatureException("Error getting key algorithm spec. Error code: " + Win32Api.getLastError());

      if ((ALG_CLASS_KEY_EXCHANGE & dwAlgId) == ALG_CLASS_KEY_EXCHANGE) {
        dwKeySpec = AT_KEYEXCHANGE;
      }
      return Advapi.cryptSignHash(hashHandle, dwKeySpec, 0);
    } finally {
      Advapi.cryptDestroyHash(hashHandle);
    }
  }
-- end of class GostR3410_2001

--class Advapi
  public static byte[] cryptSignHash(int hashHandle, int keySpec, int flags) {
    final IntByReference len = new IntByReference();
    if (!lib.CryptSignHashA(hashHandle, keySpec, null, flags, null, len))
      throw raiseError("CryptSignHash", getLastError());
    final byte[] sign = new byte[len.getValue()];
    if (!lib.CryptSignHashA(hashHandle, keySpec, null, flags, sign, len))
      throw raiseError("CryptSignHash", getLastError());
    return sign;
  }
-- end of class Advapi