yenc is a common encoding-schema for usenet posts. This is only regarding singlepart encoding.

Structure:

=ybegin line=128 size=111401 name=al_larsonbw030_ball.jpg
… data …
=yend size=111401 crc32=abcdef12

• Version 1 standard: http://www.yenc.org/yEnc-draft-1.txt
• Version 1.3 standard: http://www.yenc.org/yenc-draft.1.3.txt

There is a newsgroup for testing purposes: alt.binaries.test.yenc Whether it is still active should be evaluated.