The =<CR> is used to indicate that the last line of the b64 data is not terminate with a newline.

Both characters will be stripped when the data is decoded.

When b64 data is embedded in an email, it is wrapped (with a newline) every 76 (b64) characters. If the input data does not end with a newline, it is necessary to indicate this so that a newline is not appended when the data is decoded. ......=<cr> is the way this is done.

Update:Right conclusion (WAD), wrong interpretation. = characters are used by Base 64 to pad the last 1 or 2 bytes of data. Each 3 input bytes becomes 4 bytes of output. If there wasn't enough data in the last group of 3-bytes of the input, then the RFC calls for 1 or 2 '='s to be appended to the output to pad the group.

The <CR> is appended to the end of every line of output. Normally each line is <76 b64 chars><cr>, with the last line shorter as required.

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
Timing (and a little luck) are everything!

In reply to Re: MIME::Base64 is (working as designed) in 5.8.2 by BrowserUk
in thread MIME::Base64 is broken in 5.8.2? by pg

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