Re: New Draft... going forward

[Thomas Roessler <roessler@xxxxxxx>]

Lutz Donnerhacke wrote:

> 3.1.1 MIME
> 
> RfC 2015 "MIME Security with Pretty Good Privacy (PGP)" [2] contains all
> information necessary to strip or apply this layer. It may make use of the
> Ascii Armor layer, but the octect stream may also encoded directly using
> MIME itself.
> 
> 3.1.2 Ascii Armor
> 
> Similar to MIME encoding, the process of ascii armor encodes an 8-bit binary
> stream of data into printable characters. Every three subsequent octets are
> mapped into four subsequent ASCII characters. Futhermore ascii armor
> encoding also appends a special CRC to detect transmission errors. In order
> to ease recognition of Ascii Armored messages, a special header and footer
> is provided.

>From RFC 2015:

   PGP can generate either ASCII armor (described in [3]) or
   8-bit binary output when encrypting data, generating a
   digital signature, or extracting public key data.  The ASCII
   armor output is the REQUIRED method for data transfer.  This
   allows those users who do not have the means to interpret
   the formats described in this document to be able extract
   and use the PGP information in the message.

To me, this sounds reasonable.

> 3.1.3 Cleartext signature framework

> Dash escaped cleartext is the ordinary cleartext where every
> line starting with a dash '-' (US-ASCII 0x2D) is prepended by
> the sequence dash '-' (US-ASCII 0x2D) and space ' ' (US-ASCII
> 0x20). This prevents the parser from recognising armor headers
> of the cleartext itself. The message digest is computed using
> the cleartext itself, not the dash escaped form. So it is
> possible to seperate or join a signature from or to a cleartext
> without resigning it.

PGP 2.6's clear text armor goes a little bit beyond RFC 1113
which defines the original dash escaped text: Lines beginning
with the five characters "From " are escaped as well.

tlr
-- 
Thomas Roessler · 74a353cc0b19 · dg1ktr · http://home.pages.de/~roessler/
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