HowTo: e-Mail Client Software

See also ImportRootCert | FAQ/BrowserClients

This HowTo tells you how you can manually import the CAcert Root Certificate in your e-mail client software.

Expected Result: You can use S/MIME or PGP/GPG siganture and encryption using CAcert-issued certificates.



DJIGZO has two separate key stores: "Certificates & Keys" for your personal keys (and intermediary certificates). But CA root certificates go into "Root certificates". So when your CA certificate is a (self-signed) root certificate, you have to add it to "Root certificates", choosing "Store to import to: root". This is in contrast to your (intermediary or end-user) certificates which are signed by a CA; they go into "Certificates & Keys" by choosing "Store to import to: certificates".

see also here:


For S/MIME encryption and/or signing, there is the Android app R2Mail2, which is a fully functional e-mail client. Unfortunately, it costs 4,80 Euros (for the license; otherwise you only see 5 messages per folder for demo). R2Mail2 is still being developed and further improved. I already find it much better than the default Android mail client. It does not have as many features as K-9 mail, but it fully supports S/MIME (and to some more limited degree also PGP).

see also here:

iOS (iPhone, iPad)

The advantage of S/MIME is that it's built into Mail in iOS. To enable this feature, you have to go into the Settings > Account > Advanced for each e-mail account, and then enable S/MIME.

PGP/GPG in (Apple) Mail

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PGP/GPG in Thunderbird

S/MIME in Thunderbird


MacOS (Macintosh)

Mac OS X includes Keychain, a built-in key and password manager, which stores user passwords, user and server certificates, and keys. Certain applications use this centralized Keychain for storing and retrieving certificate information in lieu of maintaining their own, separate certificate repositories.

The advantage of S/MIME is that it's built into Mail on the Mac.

To import your certificate-key pair:

Once imported, your certificate-key pair will appear under both the Certificates and Keys categories in the Keychain Access utility.

Apple Mail

Deutsche Anleitung

S/MIME in (Apple) Mail


S/MIME in Entourage



see Linux

Outlook for OS X


S/MIME in Outlook 2003


S/MIME in Outlook 2007


S/MIME in Outlook 2010

see: HowToDocuments/Outlook%202010


see Linux

CategoryCommunity CategoryConfiguration CategoryGuide CategorySoftware CategorySupport

FAQ/eMailClients (last edited 2015-06-29 18:22:28 by AlesKastner)