Terence Dowling terry at tdowling.com
Sat May 17 00:19:33 CEST 2014

OK, So we must deal with the legacy of "as-built" rather than "as-designed".

Therefore I suggest that  wording (wordsmiths welcome) be added to the
DSIG table documentation:


"DSIG was originally intended to provide some assurance of the
provenance and integrity of a font object.

Implementations have so compromised this feature such that
DSIG no longer offers any protection and its only remaining
value is that some implementations use the presence of this
table to differentiate between "legacy TrueType" and "OpenType".

As a result, no font processor may reject or otherwise devalue a
font with a DSIG that does not validate properly or promote a
font with a DSIG that does validate."


Again, prudence suggests (requires?) that we provide clear notice
that there is no longer any integrity benefit provided by DSIG.

In an environment of security challenges (including fonts as a threat
vector), can we do less?

It seems unfortunate that there has been no clear enumeration of
products/versions that use a presence test for DSIG that would guide
font production testing.

Terence Dowling

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