Darren,
The goal of the S/MIME WG is to design the S/MIME v3 set of specs such that
they meet the secure e-mail messaging requirements validated by the WG while
maximizing backwards compatibility with the significant installed base of
S/MIME v2 products. I use the term "backwards compatibility" to mean that
it is possible to select the options and algorithms when constructing an
S/MIME v3 message such that S/MIME v2 agents can successfully process that
message, and vice versa. I did not mean to imply in my previous message
that "backwards compatibility" is a silver bullet to shoot down any new
proposal. However, when we debate new proposals, I believe that we must
consider the backwards compatibility issue and design the specs to
accommodate that feature when possible. I believe that we have done an
excellent job so far of adding new features without breaking backward
compatibility.
Darren wrote:
For example, why is there no extension mechanism, like X.509s, in
SignedData?
IMHO, Phillip's proposal to define an attribute consisting of a SEQUENCE of
attribute-like structures each of which includes a crticality flag meets
that requirement.
Darren wrote:
Let's change the name to SIM (Secure Internet Mail) and get rid of the
reliance on
MIME encodings and allow the passing of arbitrary binary data.
That contradicts the S/MIME WG charter which states that the WG will "define
MIME encapsulation of digitally signed and encrypted objects whose format is
based on PKCS #7".
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John Pawling
jsp(_at_)jgvandyke(_dot_)com
J.G. Van Dyke & Associates, Inc.
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