On 23/May/11 22:04, Hector Santos wrote: > Alessandro Vesely wrote: >> On 23/May/11 06:35, Hector Santos wrote: >>> Alessandro Vesely wrote: >>> >>>> For example, MTAs that autoconvert from quoted-printable to 8bit, a >>>> rather common circumstance. >>> I did the following Content-Transfer-Encoding failure analysis: >>> >>> Failure rates for message top level encoding type >>> +--------------------------------------------------------+ >>> | enctype total bodyfail pct | >>> |--------------------------------------------------------| >>> | 8bit 31 25 80.6 | >> >> It is not clear what part of these 8bit failures is due to messages >> that had been downgraded before signing, and then upgraded before >> verifying. > > None.
Sorry, by "upgraded" I mean the same as "X-MIME-Autoconverted: from /any encoding/ to 8bit". Thus I take your answer as 20/31. > Of the 31, 20 were from Keith Moore signed messages into the IETF-SMTP > list with a 3rd party signature and Hoffman's list server (non-dkim > aware) doing this: > > Content-Transfer-Encoding: 8bit > X-MIME-Autoconverted: from quoted-printable to 8bit by > hoffman.proper.com id p4BLC7Hl032165 Thanks! It was recently mentioned that Hoffman's MLM inserts a white line on top of the body. Unfortunately, relaxed body canonicalization regards this line as significant. This autoconversion is another, unrelated change that breaks signatures. Now, let me say that my MTA contravenes the "SHOULD downgrade" precept. I hypothesize that if it wasn't for the extra white line, that is, taking into account only "normalization" issues, then my signatures would survive while Keith's would not. IOW: the 1st paragraph of Section 5.3 can be *misleading*, as in some cases a signature's survivability gets worsened. What encoding minimizes the chances of conversion is a moving target whose current state we should not purport to know. _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html