public static SignatureAlgorithm valueOf(int ord) {
            try {
                return values[ord];
            } catch (IndexOutOfBoundsException e) {
                throw new IllegalArgumentException("Invalid signature algorithm " + ord, e);
            }
        }
DigitallySigned structure, as defined by RFC5246 Section 4.7.
common/src/main/java/org/conscrypt/ct/DigitallySigned.java