x00, xEF, xC8 - what type of format are these?

Question

I base64 decoded a string and I now have a string made up of 'X00', 'xEF', 'xC8' etc...

What are these (characters?), or can they be decoded into something else?

I Want to learn more about it, but can't find anything on Google.

Thanks

(I had no idea what to enter as a tag so feel free to amend it)

Answer 1

they look like hex numbers but they could be unicode characters ...

\xEF as unicode = ï == u"\u00ef"

http://www.fileformat.info/info/unicode/char/ef/index.htm

but I think they are hex numbers