New Tor 0.2.4.16-rc packages and updated stable Tor Browser Bundles

Encrypted email is simply a marriage of a text encryption utility and an email utility that does all of the "work" for you:

It encrypts the email text you write (using your public and private keys - assuming you are using simple assymmetric encryption like GPG);

On the recipients end, it looks up your public encryption key and decrypts the message (leaving it encrypted only with your private key);

Then it re-encrypts the message with the recipient's private and public keys, and returns the encrypted message to you;

The utility then decrypts the message with the recipient's public key and your private key, and returns it encrypted with the recipient's public and private keys.

The utility then decrypts the message into clear text using the recipient's public and private keys.

Using a utility, this all happens in the background and reasonably quickly, so you don't really notice it.

[And, this explanation is theoretical to explain exactly how assymetric dual-key encryption works. In the real world, the actual operations might be different, but the practical effect - the message is always "locked" by two levels of encryption, one public and one private - is the same.]

You can do the same thing with text encryption. It is just more work for the user.

I can encrypt this message with my public and private keys.

When you receive it, you will be able to see the encrypted text, but not read it.

You will have to know where my public key is kept, decrypt the message using that, re-encrypt it using your public and private keys, and return it to me.

I will decrypt it with my private key, and return it to you encrypted with your public and private keys. (I, of course, will not be able to read it, since I don't have your private key, but it's my message, so I know what it says.)

You will then be able to decrypt it to clear text using your keys.

One, less secure but more convenient, alternative is that I could just encrypt the message with a public key and send it to you anonymously (using a pseudonym known to each of us but not to anyone else). You could then decrypt it with the pseudononymous public key. If I use 2048 or 4096 bit encryption, as a practical matter this method of exchanging encrypted text would be almost as secure as dual-key encryption PROVIDED NOBODY FIGURES OUT THE PSEUDONYM (This is a huge qualification, to say the least! It probably means that I could not use any pseudonym more than once.)

In short, an email encryption utility simply performs a bunch of administrative steps that make exchange of encrypted text both reliable and practical. For those who desire anonymity and privacy and are willing to make the effort, the availability of text encyption alone will suffice, but will be much less convenient.