Archaic scripts

Lisa Dusseault ldusseault at
Fri May 9 15:58:04 CEST 2008

On May 8, 2008, at 4:01 PM, Erik van der Poel wrote:

> If we lock down the DISALLOWED set too tightly, we may regret it
> later. One way to avoid locking it down is to recommend that
> burned-in-ROM and other unupgradable software only use protocols that
> use LDH- and A-labels. All pieces of software, whether IDNA-aware or
> not, are explicitly permitted to look up Punycode labels, without
> decoding them to check for DISALLOWED, CONTEXT*, etc.

Not that this point is essential to most of your argument, but  
recommending that unupgradable software only use certain protocols is  
a completely infeasible requirement or recommendation for the IETF to  
make.  Even if we thought such a recommendation would be paid  
attention to, there's no bright line between "upgradable" and  
"unupgradable" software -- even software that is in theory upgradable  
is often in practice locked into particular versions for years,  
skipping even vital security upgrades.  So even if implementors  
followed such a requirement, we still can't expect timely upgrades of  
codepoint listings.

There's also no bright line between protocols or software that use  
LDH- and A-labels and those that don't, right?  As you point out, even  
IDNA-unaware software may look up Punycode labels, and naturally those  
implementations won't follow requirements we make on limiting lookups.


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