Re: [nmh-workers] mhshow: invalid BASE64 encoding in --

[Valdis Klētnieks]

On Sun, 17 Mar 2019 09:28:53 -0400, David Levine said:

> More generally, what if a sender (improperly) had annotated an already
> encoded message with, say, "DO NOT FORWARD THIS!"?  Bad, yes, but could lead 
> to
> undesired results if that was dropped.

My reading of RFC2045 says a conforming base64 decoder is allowed to toss out
the blanks and the '!' char and decode the rest.

   Any characters outside of the base64 alphabet are to be ignored in
   base64-encoded data.

Yeah.  That's pretty definitive. :)

Which means your sender just prepended the string '?NLSXCLr' to the message
(where the ? is an 'lower case a with circumflex')

Somehow, I doubt that's going to stop it from being forwarded.

> In other words, I'd like to see all of the content or an error message.

Oh, and what happens if a conforming implementation takes that
'you are receiving this message' whoopsie and decodes it?

This.  Which is probably *not* what you meant by 'see all of the content'.

base64-blam.png
Description: base64-blam.png