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.
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