static byte[] ecSignDigestWithPrivateKey(PrivateKey javaKey, byte[] message) {
        // Hint: Algorithm names come from:
        // http://docs.oracle.com/javase/6/docs/technotes/guides/security/StandardNames.html
        String keyAlgorithm = javaKey.getAlgorithm();
        if (!"EC".equals(keyAlgorithm)) {
            throw new RuntimeException("Unexpected key type: " + javaKey);
        }

        return signDigestWithPrivateKey(javaKey, message, "NONEwithECDSA");
    }
Finds providers that are not us that provide the requested algorithms.
common/src/main/java/org/conscrypt/CryptoUpcalls.java