[B][I][CENTER]One of the interesting pieces of functionality that I think Zimbra is missing is support for verified and secure communication.
In particular there is very similar functionality needed for bugs: 9046 - S/MIME Support, 6158 - PGP Support, and 13108-Domain Key Supports and finally 17147 - OpenID. These bugs all revolve around identification/verification (in other words, signing and validation) and encryption/decryption.
The basic idea is that we want to allow the user to securely send email without compromising keys,
Key creation/deletion with passphrase and arbitrary key length.
Key stores in armored ASCII and PKR/SKR work.
Key's can be signed to validate identity
RSA and El GAmel keys work.
Message encryption/decryption in armored ASCII works.
Binary encryption/decryption works.
There is a pretty good JUNIT testing framework for all of this.
Flatfile keystores work fine.
Key's can be imported from other keyservers.