https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/examples/ShakeTruncation.pdf
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Samples to illustrate the proper truncation of SHAKE
outputs for output lengths that are not multiples of
8-bits.
All samples below use SHAKE128 with a 0-bit input
message (the “empty” or “null” message).
Note - Only the final byte changes to accommodate the
convent...