private synchronized static Key getDecryptKey(String algorithm) {
        Key key = DECRYPT_KEYS.get(algorithm);
        if (key != null) {
            return key;
        }
        try {
            if (algorithm.startsWith("RSA")) {
                KeyFactory kf = KeyFactory.getInstance("RSA");
                RSAPrivateCrtKeySpec keySpec = new RSAPrivateCrtKeySpec(RSA_2048_modulus,
                        RSA_2048_publicExponent, RSA_2048_privateExponent, RSA_2048_primeP,
                        RSA_2048_primeQ, RSA_2048_primeExponentP, RSA_2048_primeExponentQ,
                        RSA_2048_crtCoefficient);
                key = kf.generatePrivate(keySpec);
            } else {
                assertFalse(algorithm, isAsymmetric(algorithm));
                key = getEncryptKey(algorithm);
            }
        } catch (Exception e) {
            throw new AssertionError("Error generating keys for test setup", e);
        }
        DECRYPT_KEYS.put(algorithm, key);
        return key;
    }
Returns the key meant for deciphering for {@code algorithm}.
common/src/test/java/org/conscrypt/javax/crypto/CipherTest.java