message: Pass `unsigned char*` as a parameter to BN_bn2binpad for both BoringSSL and OpenSSL.
diff: @@ -36,13 +36,8 @@ util::Status BignumToBinaryPadded(absl::Span<char> buffer,
  }
  // BN_bn2binpad returns the length of the buffer on success and -1 on failure.
  -#ifdef OPENSSL_IS_BORINGSSL
  - int len = BN_bn2binpad(bignum, reinterpret_cast<uint8_t *>(buffer.data()),
  - buffer.size());
  -#else
  int len = BN_bn2binpad(
  bignum, reinterpret_cast<unsigned char *>(buffer.data()), buffer.size());
  -#endif
  if (len == -1) {
  return util::Status(absl::StatusCode::kInternal,
  "Value too large to fit into the given buffer");
  