private static int parseVersion(final String part) {
        if (!part.startsWith("v=")) {
            throw new IllegalArgumentException("Did not find version parameter 'v='. Got: [" + part + "].");
        }

        return Integer.parseInt(part.substring(2));
    }
128 bits of salt is the recommended salt length, taken from draft-irtf-cfrg-argon2-13, 4.2.
crypto/support/hashes/argon2/src/main/java/org/apache/shiro/crypto/support/hashes/argon2/Argon2Hash.java