padding. Sections 6.1 and 6.2 of [1] separate the outputs of the // SHA-3 and SHAKE functions by appending bitstrings to the message. // Using a little-endian bit-ordering convention, these are "01" for SHA-3 // and "1111" for SHAKE, or 00000010b and 00001111b, respectively. Then the // padding rule from section 5.1 is applied to pad the message to a multiple // of the rate, which involves adding a "1" bit, zero or more "0" bits, and // a final "1" bit. We merge the first "1" bit from the padding into...