Subject: Re: Base64

From: Harald Alvestrand <[email-masked]>
Date: Wed, 16 Jan 2002 14:00:15 +0100

--On fredag, desember 21, 2001 18:55:47 +0100 Daniel Kraft 
<[email-masked]> wrote:

> Does the base64-algorithm encode a string to a string which uses 7 bits
> fully (so to say a 7-bit-binary string)?
> Or uses it only 6 bits fully (I mean, if all bits can have a value of 0 or
> 1, and not, that some bits have a fixed value)?

64 different characters (thence its name).
This COULD have been represented in 6 bits, the 2 remaining ones held 
constant, but isn't.
The set of 64 characters was chosen so that characters likely to be mangled 
by mail gateways existant at the time were not used.
At that time, for instance, it was likely that | (verticalbar) would turn 
into o (lower case O) if it passed a Bitnet gateway in Scandinavia.

Luckily, a lot of those gateways are now a thing of the past.

>
> Daniel
>
> PS: Sorry for spelling or grammar mistakes!
> ---
> http://www.daniel-kraft.net/
>
> -
> This message was passed through [email-masked], which
> is a sublist of [email-masked]. Not all messages are passed.
> Decisions on what to pass are made solely by Raffaele D'Albenzio.
>