For the love of computing: Did you mean 0 or O?

We have all been in the position of not knowing if we have a zero (‘0’) or an ‘O’. So how do we avoid this? Well in the encoding of non-printing characters to printable ones we often Base-64, where we take six bits at a time and convert to a Base-64 character.

But what about similar-looking letters : 0 (zero), O (capital o), I (capital i) and l (lower case L), and non-alphanumeric…