Java 类java.security.DrbgParameters.Instantiation 实例源码

/**
 * Verify the exception type either it is expected to occur or not.
 * @param alg Algorithm name
 * @param param DRBG parameter
 * @param e Exception to verify
 * @throws NoSuchAlgorithmException
 */
private static void checkException(String alg, SecureRandomParameters param,
        NoSuchAlgorithmException e) throws NoSuchAlgorithmException {

    int strength = ((Instantiation) param).getStrength();
    boolean error = true;
    switch (alg) {
        case INVALID_ALGO:
            error = false;
            break;
        case "SHA-224":
        case "SHA-512/224":
            if (strength > 192) {
                error = false;
            }
            break;
        case "SHA-256":
        case "SHA-512/256":
        case "SHA-384":
        case "SHA-512":
            if (strength > 256) {
                error = false;
            }
            break;
        case "AES-128":
        case "AES-192":
        case "AES-256":
            int algoStrength = Integer.parseInt(alg.substring("AES-".length()));
            int maxAESStrength = Cipher.getMaxAllowedKeyLength("AES");
            if (strength > algoStrength
                    || algoStrength > maxAESStrength) {
                error = false;
            }
            break;
    }
    if (error) {
        throw new RuntimeException("Unknown :", e);
    }
}

/**
 * Verify the exception type either it is expected to occur or not.
 * @param alg Algorithm name
 * @param param DRBG parameter
 * @param e Exception to verify
 * @throws NoSuchAlgorithmException
 */
private static void checkException(String alg, SecureRandomParameters param,
        NoSuchAlgorithmException e) throws NoSuchAlgorithmException {

    int strength = ((Instantiation) param).getStrength();
    boolean error = true;
    switch (alg) {
        case INVALID_ALGO:
            error = false;
            break;
        case "SHA-224":
        case "SHA-512/224":
            if (strength > 192) {
                error = false;
            }
            break;
        case "SHA-256":
        case "SHA-512/256":
        case "SHA-384":
        case "SHA-512":
            if (strength > 256) {
                error = false;
            }
            break;
        case "AES-128":
        case "AES-192":
        case "AES-256":
            int algoStrength = Integer.parseInt(alg.replaceAll("AES-", ""));
            int maxStrengthSupported = Cipher.getMaxAllowedKeyLength("AES");
            if (strength > maxStrengthSupported
                    || algoStrength > maxStrengthSupported) {
                error = false;
            }
            break;
    }
    if (error) {
        throw new RuntimeException("Unknown :", e);
    }
}

public static void main(String[] args) throws NoSuchAlgorithmException {
    Instantiation instantiation = DrbgParameters.instantiation(128, RESEED_ONLY, null);
    SecureRandom random = SecureRandom.getInstance("DRBG", instantiation);

    byte[] bytes = new byte[20];
    random.nextBytes(bytes);
    for (byte b : bytes) {
        System.out.print(b + " ");
    }
    System.out.println();
}

private static boolean isSupportPR(String mech, SecureRandom random) {
    return (isDRBG(mech) && ((Instantiation) random.getParameters())
            .getCapability()
            .supportsPredictionResistance());
}

private static boolean isSupportPR(String mech, SecureRandom random) {
    return (isDRBG(mech) && ((Instantiation) random.getParameters())
            .getCapability()
            .supportsPredictionResistance());
}