The Unicode Consortium has released three important specifications related to Internationalized Domain Names (IDNs) and Security.
Client software, such as browsers and emailers, faces a difficult transition from the version of international domain names approved in 2003 (IDNA2003), to the revision approved in 2010 (IDNA2008). The specification in this document provides a mechanism that minimizes the impact of this transition for client software, allowing client software to access domains that are valid under either system. The specification provides two main features: One is a comprehensive mapping to support current user expectations for casing and other variants of domain names.
Such a mapping is allowed by IDNA2008. The second is a compatibility mechanism that supports the existing domain names that were allowed under IDNA2003. This second feature is intended to improve client behavior during the transitional period.
Because Unicode contains such a large number of characters and incorporates the varied writing systems of the world, incorrect usage can expose programs or systems to possible security attacks. This is especially important as more and more products are internationalized.
This document describes some of the security considerations that programmers, system analysts, standards developers, and users should take into account, and provides specific recommendations to reduce the risk of problems.
Because Unicode contains such a large number of characters and incorporates the varied writing systems of the world, incorrect usage can expose programs or systems to possible security attacks. This document specifies mechanisms that can be used to detect possible security problems.
In Malayalam there are two prevailing orthographies, traditional and reformed. Both are written using the same Malayalam character set. The difference between them is typically manifested only by the font. Traditional orthography accommodates more full conjuncts, while the reformed orthography would use visible virama (Chandrakkala) separated sequences for many of those full conjuncts.
This proposal specifies the further use of ZWJ and ZWNJ in sequences in the Malayalam script to indicate preferences for optional display of conjuncts. Such sequences are intended to indicate the preferences, both for rendering systems that support the reformed Malayalam orthography and for systems that support the traditional Malayalam orthography.
The UTC is seeking feedback on this proposal, regarding its advisability and potential impacts on implementations, as well as any suggestions for alternative approaches to the issues raised in the background document.