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Re: Base-64 proposal

At 08:12 AM 4/16/97 EDT, Ron Rivest wrote:
>* How do you represent a left brace in augmented 8-bit mode?
>  The natural answer is as follows:
>	A left brace is octal 173 = binary 01111011
>	which breaks into hextets as 011110 11xxxx  (x = doesn't matter)
>	Then 011110 encodes as "e"
>	and  11xxxx encodes as "g" (as one possibility)
>  Thus, by writing
>	{eg}
>  in the augmented 8-bit channel, you get a left brace into the output
>  ordinary 8-bit channel.
>  One could introduce other mechanisms for accomplishing this as well, but
>  this is sufficient.  One natural alternative would be to let "\{" in the
>  augmented channel produce "{" in the output, and "\\" in the input 
>  produce "\" in the output.  But this requires two active characters
>  left brace and backslash, which seems overkill.  I suggest that we
>  not introduce redundant mechanisms.

Another option, since "{" isn't part of the 64-character alphabet,
is to accept "{{" or "{{}" as a left brace.  May be more trouble than
it's worth, given that "{eg}" works directly, but it doesn't require
magic behaviour for two different characters.

#			Thanks;  Bill
# Bill Stewart, +1-415-442-2215 stewarts@ix.netcom.com
# You can get PGP outside the US at ftp.ox.ac.uk/pub/crypto/pgp
#     (If this is a mailing list, please Cc: me on replies.  Thanks.)

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