>> "Rainer" == Rainer M Krug <Rainer> writes:

   > Hi
   > At the moment I am using OpenPGP to sign and encrypt my emails, but
   > this does not work easily on my iPhone (please tell me otherwise if it
   > does?).

No it is not, unfortunately. There is no native support and the 3rd
party pkgs are not terrible easy to use, since they are not integrated
with the email reader. One of them is even not gpg conform and it was
impossible to import an old gpg key of mine.

This was one of the reasons for me to switch to smime.

   > But the iPhone implements S/MIME encryption. Now what are the
   > advantages of using each as a standard signing / encryption? Which
   > one is better / safer? I have OpenPGP working via gnus on a Mac and
   > am happy with it.

Both use  a-symmetric encryption and are both safe, what is radially
different is the distribution of public keys. Pgp/gpg has a key model in
which you generate your key pair and distribute your public key or
uplaod it to a server. The problem is not safety but authency  so in gpg
you hope that your key on the server gets signed but a sufficient amout
of trustworthy people.

Smime has a hirachical model. There are a couple of organisations with
posses a root certificate in which signed public keys (called
certificates). You typically apply for such a certificate (a process in
which the encryption module of your bowswer generate your private key),
the authority then allows you to download your certificate signed by
their root certificate, confirming usually only the authenticity of your
email address.

   > So - what are others using and why? Should I use S/MIME instead?


Well it is much easier to use and also easier to convince others to use
it as well, because


    -  It is integrated in your email reader usually. 

    - You do not have to generate a key pair for your self.

    - And you do not need to exchange the public keys, they are
      automatically included in your signature.

    -  it is compatible with the iPhone.

cheers

Uwe Brauer