L2/13-038
Re: Clarify UTS #39 Security Mechanisms
From: Mark Davis, Andy Heninger
Date: Jan 29, 2013
There are some small changes that should be made to #39:
http://www.unicode.org/reports/tr39/#Confusable_Detection
1. There are a few crucial definitions for single/mixed/whole-script confusables. We need a tweak to the first definition, and all of the definitions need to be highlighted.
OLD
X and Y are single-script confusables if they are confusable according to the Single-Script table, and each of them is a single script string according to Section 5, Mixed-Script Detection. Examples: "so̷s" and "søs" in Latin, where the first word has the character "o" followed by the character U+0337 ( ̷ ) COMBINING SHORT SOLIDUS OVERLAY.
NEW
X and Y are single-script confusables if they are confusable according to the Single-Script table, and each of them is a single script string according to Section 5, Mixed-Script Detection, and it is the same script. Examples: "so̷s" and "søs" in Latin, where the first word has the character "o" followed by the character U+0337 ( ̷ ) COMBINING SHORT SOLIDUS OVERLAY.
http://www.unicode.org/reports/tr39/#Restriction_Level_Detection
2. We need to add text to make it clear that Common and Inherited are ignored when computed Restriction Levels. (The algorithm references http://www.unicode.org/reports/tr39/#Mixed_Script_Detection which does this, but it should be clear from the text also.)
OLD
All characters in each identifier must be from a single script, or from the combinations:
NEW
All characters in each identifier must be from a single script (excluding Common and Inherited), or from the combinations:
3. We should also add another Restriction Level between ASCII and Highly Restrictive, since people have found that to be useful also.
NEW
Single Script