protected static HpkeSpi findSpi(String algorithm, String providerName) throws
      NoSuchAlgorithmException, IllegalArgumentException, NoSuchProviderException {
    if (providerName == null || providerName.isEmpty()) {
      // Same behaviour as Cipher.getInstance
      throw new IllegalArgumentException("Invalid provider name");
    }
    Provider provider = Security.getProvider(providerName);
    if (provider == null) {
      throw new NoSuchProviderException("Unknown Provider: " + providerName);
    }
    return findSpi(algorithm, provider);
  }
Returns the {@link HpkeSpi} being used by this HpkeContext.

@return the SPI
common/src/main/java/org/conscrypt/HpkeContext.java