
ASCII bit trick to convert lowercase to uppercase and back - benigeri
http://www.catonmat.net/blog/ascii-case-conversion-trick/
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peff
For a fun application, this trick is used in a proposal to encode extra
randomness into the 0x20 bit of each character of a DNS query (to increase
resistence to poisoning attacks):

<https://tools.ietf.org/html/draft-vixie-dnsext-dns0x20-00>

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pan69
Is it a "trick" if the designers of the original ASCII chart obviously
designed it like this?

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pixelbeat
Yes ASCII (and UTF-8) were designed well.

<http://www.pixelbeat.org/docs/utf8_programming.html>

