Should we add a Glossary to the book?

[kbeyls]

[sam-ellis]

I think it depends on how many terms exist that need explaining and whether these are used throughout the book that warrants a glossary definition or whether they are localized such that a local definition will suffice. Thus far I think we have the term "side-channel" that would benefit from a glossary definition. Perhaps if we can reach (say) 5 such terms, then a glossary is beneficial.