The current spec and implementation expect everything passed in (byte array/ String/ByteBuffer) are acceptable valid base64 data, if there is anything (trailing bytes) left can't be handled by the decoder, it's an "error". In case of MIME, the spec explicitly specifies any non-bsae64 character are ignored, so even they are not valid base64 bits, but they should be accepted and ignored, as part of the valid base64 data, not the "trailing" stuff (the mime decoder skips those bytes in the middle of data, it would be consistent to also skip at the end)
OK, I think I got it now. -Chris.
