Users Digest, Vol 31, Issue 13

Looking at doing a project and have played with Djigzo for a few
hours (On CentOS5) and am trying to figure out if it will work for
our needs. It is not looking promising. I'm using Thunderbird here
in all cases.

1) I can't seem to figure out how to get every user's SMIME cert to
every other user. Example: I've createdjohnny(a)bar.baz and
sammy(a)bar.baz. I created the internal CA, created a cert for both
of them and imported it. But, at that point, how do I send an
encrypted message between Johnny and Sammy? Without Sammy having
Johnny's keys and vice-versa, there isn't a way to encrypt the
outgoing message. On the certificates page, there is an option to
"download all keys." But aren't these the private keys? I wouldn't
want every user to have every user's private keys.

If you select the certificates and click "download keys" it will
download the keys but if you select "download certificates" it will
only download the certificates (without the keys). All the
certificates for all your internal users should be exchanged between
clients. The easiest way to do this is by selecting all the
certificates for your users, and then click "download certificates".
This will give you a .p7b file containing all certificates. This .p7b
file can then be imported into every desktop.

Is there a "special" way to import certificates into Thunderbird? Or
are the certificates not imported into Thunderbird? Exporting the
certificates does not prompt for a password. Trying to import the p7b
into Thunderbird prompted for a password.

2) Is there any way to prevent Djigzo from DEcrypting incoming
messages?

If all users are external users (the default), then no email will be
decrypted. Incoming email is split into two paths, for internal
recipients email will be decrypted, for external recipients email will
be encrypted. If you do not make any domain or user an internal user,
no email will be decrypted.

Essentially, here's what I'm looking for: -- All messages in a user's
mail folders are SMIME encrypted. -- Any incoming mail that is SMIME
encrypted for that user passes untouched.
-- Any incoming mail that is unencrypted is encrypted by Djigzo
using the user's own key. -- Any outgoing mail that is encrypted is
untouched -- Any outgoing mail that is unencrypted is untouched.

I think that Djigzo ends up being total overkill in this situation?

I have been thinking about such a use case as well because it can be
used to store all email encrypted in your local mailbox. This is kind
of different from the typical use case of the Djigzo gateway. If you
make sure that every user is an external user, this should work since
all incoming email for some internal user will be encrypted if it is
not already encrypted (if setup to encrypt all email for certain
users). How are your internal users going to send encrypted email to
each other? Using the S/MIME functionality of the email client?

Yes this is the assumption. If the users import "all" of the
certificates, then wouldn't they be able to encrypt email going to
another user? If the user Johnny sends an unencrypted email to the user
Sammy on the same server, but they are both "external" users, isn't
Djigzo going to encrypt the incoming message?

EX: Sammy sends email to Johnny unencrypted. Djigzo will use Johnny's
key to encrypt the message before it is passed along to Johnny?

···

On 11/24/2011 6:00 AM, users-request(a)lists.djigzo.com wrote:

On 11/24/2011 05:07 AM, Erik Jacobs wrote:

1) I can't seem to figure out how to get every user's SMIME cert to
every other user. Example: I've createdjohnny(a)bar.baz and
sammy(a)bar.baz. I created the internal CA, created a cert for both
of them and imported it. But, at that point, how do I send an
encrypted message between Johnny and Sammy? Without Sammy having
Johnny's keys and vice-versa, there isn't a way to encrypt the
outgoing message. On the certificates page, there is an option to
"download all keys." But aren't these the private keys? I wouldn't
want every user to have every user's private keys.

If you select the certificates and click "download keys" it will
download the keys but if you select "download certificates" it will
only download the certificates (without the keys). All the
certificates for all your internal users should be exchanged between
clients. The easiest way to do this is by selecting all the
certificates for your users, and then click "download certificates".
This will give you a .p7b file containing all certificates. This .p7b
file can then be imported into every desktop.

Is there a "special" way to import certificates into Thunderbird? Or
are the certificates not imported into Thunderbird? Exporting the
certificates does not prompt for a password. Trying to import the p7b
into Thunderbird prompted for a password.

Exporting the certificates from Djigzo does not require a password. A
.p7b (or .cer) is not a password protected file. Thunderbird probably
requires you to enter the master password (set by the owner of
Thunderbird) to allow the import of certificates and/or keys.

2) Is there any way to prevent Djigzo from DEcrypting incoming
messages?

If all users are external users (the default), then no email will be
decrypted. Incoming email is split into two paths, for internal
recipients email will be decrypted, for external recipients email will
be encrypted. If you do not make any domain or user an internal user,
no email will be decrypted.

Essentially, here's what I'm looking for: -- All messages in a user's
mail folders are SMIME encrypted. -- Any incoming mail that is SMIME
encrypted for that user passes untouched.
-- Any incoming mail that is unencrypted is encrypted by Djigzo
using the user's own key. -- Any outgoing mail that is encrypted is
untouched -- Any outgoing mail that is unencrypted is untouched.

I think that Djigzo ends up being total overkill in this situation?

I have been thinking about such a use case as well because it can be
used to store all email encrypted in your local mailbox. This is kind
of different from the typical use case of the Djigzo gateway. If you
make sure that every user is an external user, this should work since
all incoming email for some internal user will be encrypted if it is
not already encrypted (if setup to encrypt all email for certain
users). How are your internal users going to send encrypted email to
each other? Using the S/MIME functionality of the email client?

Yes this is the assumption. If the users import "all" of the
certificates, then wouldn't they be able to encrypt email going to
another user? If the user Johnny sends an unencrypted email to the user
Sammy on the same server, but they are both "external" users, isn't
Djigzo going to encrypt the incoming message?

EX: Sammy sends email to Johnny unencrypted. Djigzo will use Johnny's
key to encrypt the message before it is passed along to Johnny?

I haven't tested this but it should work if you make sure that the
Djigzo gateway is the one your users connect to. If you are using a
different server your users connect to and that server handles email for
local accounts locally (for example the mail boxes are stored on the
same server), the email for local users is not relayed through the
Djigzo server.

Kind regards,

Martijn Brinkers

···

On 11/24/2011 02:14 PM, Erik Jacobs wrote:

On 11/24/2011 6:00 AM, users-request(a)lists.djigzo.com wrote: