I've seen many RegEx answers on how to check for Base64, but I can't find one specifically for representations of 256-bit numbers.
I'm brand new to Base64, byte conversions, and RegEx. This answer seems to be the best for checking Base64, but I can't tell from the details if it can be specifically applied to a representation of a 256-bit number.
^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$
I need to make sure of the validity of these strings because I'm using them as encodings of Ed25519 keys, and my en/decoder seems to accept non-ASCII characters.
I don't really understand if that can specifically be applied to a representation of a 256-bit number.
How can RegEx validate a Base64 encoded 256 bit number?