Sender authentication part 30: The canonicalization process

re: Sender authentication part 30: The canonicalization process

Norman Diamond — Wed, 03 Oct 2007 03:48:26 GMT

I just noticed that even today e-mail messages with ISO-8859-1 character set are encoded into sequences of 7-bit characters in order to traverse mail servers. On the web you can get encodings into sequences of 8-bit characters (UTF-8 and national encodings) but in e-mail they're encoded into sequences of 7-bit characters (UTF-7 and national encodings).

When creating a new message in Outlook Express, it offers one possibility as encoding into UTF-8, but I wonder how that fares when going through mail servers.

re: Sender authentication part 30: The canonicalization process

Norman Diamond — Wed, 26 Sep 2007 05:05:29 GMT

> All email was once 7-bit ASCII

In ancient history that was true. Subsequently (and still anciently) escape sequences were added to shift into and out of various encoding modes for most of the world's written languages.

> and now most of it is 8-bit ASCII.

There is no such thing as 8-bit ASCII. Most ANSI code pages are 8-bits, and ISO-8859 encoding schemes are 8-bits. Some ANSI code pages are mixtures of 8 and 16 bits. ISO-2022 schemes encode 16-bit characters in sequences of 8-bit bytes. UTF-8 does the same. Anyway, ASCII is still 7-bits, ASCII is essentially a 7-bit ANSI code page, and even .Net gets that part right.

(I don't think UTF-16, as used by Windows NT-series APIs and .Net, can be sent through e-mail without the coding being changed to UTF-8.)

Techy News Blog » Sender authentication part 30: The canonicalization process

Techy News Blog » Sender authentication part 30: The canonicalization process — Tue, 25 Sep 2007 19:21:01 GMT

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