// rfc3961 test vectors
        verifyNfold(64, "012345", "be072631276b1955");
        verifyNfold(56, "password", "78a07b6caf85fa");
        verifyNfold(64, "Rough Consensus, and Running Code", "bb6ed30870b7f0e0");
        verifyNfold(168, "password", "59e4a8ca7c0385c3c37b3f6d2000247cb6e6bd5b3e");
        verifyNfold(192, "MASSACHVSETTS INSTITVTE OF TECHNOLOGY", "db3b0d8f0b061e603282b308a50841229ad798fab9540c1b");