I had several discussions with other vendors of mail encryption gateways
and all told me that I'm wrong. But today Ciphermail did some thing I've
predicted and proved that I was right.
This is what I think, please correct me if I'm wrong:
For me s/Mime (like PGP) is a encryption system based on public and
private keys. If some one has access to the public key he can encrypt
some thing which only can be decrypted with the private key. So, when
some one sends an s/Mime signed mail to me I should be able to send a
encrypted mail to him even if I do not have a s/Mime certificate for my
e-mail address on my system.
Exactly this happened on my site with Ciphermail. I have a s/Mime
certificate for my e-mail addresses imported in Ciphermail and some one
else sent a signed mail to me. With this mail Ciphermail stored the
public key of the third party. When I mail to him Ciphermail does what I
would expect and encrypts the mails. Yesterday a other mail user of my
site which has no certificate in Ciphermail received a mail from exact
the same person and replied. The reply got encrypted by Chiphermail
despite the sender has no certificate imported to Chiphermail. This was
what I would expect to happen.
Bravo Ciphermail! :-) And thank you Ciphermail! You proved me right!
I had a discussion with the support of an other encryption gateway and
asked them, why mail sent to me from the other site got not encrypted
despite the system recorded my signature with my public key. They told
me that the mail do not get encrypted because the *sender* does not have
a certificate imported to their system and that it is impossible to send
s/Mime encrypted mails without a certificate for the *sender*.
And now Cipher mail did exactly that.
Please tell me: Is this a misbehavior of Ciphermail and does it not
conform to the standard? I don't think so.
I think that when I use a MUA to send encrypted mail it is very
important to have a certificate installed in the MUA because this is the
only way to encrypt the mail to the recipient AND to myself so I'm also
able to read what I've sent. But when a gateway doe the work it is not
mandatory that the sender has a certificate to send an encrypted mail.
MHC SoftWare GmbH
HR Coburg: B2242
Geschäftsführer: Matthias Henze