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Re: [tor-talk] Transparent e-mail encryption?
encrypted email and messenger solution.
2012/7/6 Matej Kovacic <matej.kovacic@xxxxxxxxx>
> I know this is a bit off-topic, but since here are people who know a lot
> about security and since I was unable to find relevant answers I would
> like to ask one question.
> PGP Corpotation has one interesting solution, called PGP Desktop Email.
> PGP Desktop Email is email encryption software that automatically
> encrypts email as it is received and sent on desktops and/or laptops,
> without affecting the end-user email experience. PGP Desktop Email
> operates as a proxy, supports the two global email encryption standards,
> OpenPGP and S/MIME and automatically discovers keys and certificates as
> So, my question is, is there something similar in opensource land?
> What solution I am looking for?
> On a server side there should be a simple script, which would
> automatically encrypt all incoming e-mail with recipient public key. All
> e-mail is then stored on a mail server in encrypted form.
> O a client side there would be nedded an application (daemon), which
> would transparent and automatic decrypt all incoming e-mail. Mail client
> would connect to this daemon, and this daemon would connect to mail
> server (through PO3 or IMAP), get messages, decrypt them and pass them
> to mail client. If daemon receives e-mail in plain text, it should pass
> warning to user. The same with GPG errors.
> What we get from this setup?
> First of all, mail messages are stored in encrypted form on a mail
> server. It is true, that attacker could break into the server and switch
> the GPG encryption off, but he cannot view already encrypted messages
> (we get past security). The other option is, that e-mail server already
> uses full disk encryption (TrueCrypt or LUKS), but the main password get
> abused (or server hacked). In that case users still have security of
> their personal mail guaranteed, at least past messages. (Analogy to LUKS
> full disk encryption and EncFS encryption of user's /home folder in
> Ubuntu: all users of a machine must have LUKS password to boot the
> machine, but when they do that, they would still need user's password to
> access his or her /home folder).
> On a client side, client can use insecure protocols, but user's mail
> would still be protected during transfer. Even if attacker get user's
> password, he would be unable to read his emial without his private key.
> This is also important when using mail client through Tor.
> Another thing is that mail client will always get unencrypted mail,
> which can be indexed. If decryption would be done in mail client,
> indexing would not be possible. However, it is important to note, that
> local storage of mail client should be enrypted (LUKS or EncFS) or
> located in a trusted environment.
> There is also not problematic if we receive already GPG encrypted
> e-mail. Mail message would be double encrypted on a mail server, but
> mail client will receive only one-time encrypted mail message and there
> will be no usability problems (no need for user to run decryption second
> time). There will also be no problems with GPG keys. Mail client looks
> for a public key of a sender, and since mail mesage would be decrypted
> by daemon, there would be no need to manually select correct key. There
> will also not be a problem with replying - usually if user receive
> encrypted mail, reply is also encrypted. Here behaviour of a replying
> would be "normal" (however messages stored in reply folder on a server
> would also be encrypted by the server), and there will be no problems
> with selection of recipient's public key. This solution can also encrypt
> complete message - including mail header.
> The only "bad thing" is that user would need additional software
> installed on his machine (this daemon), that mail admin should install
> the encryption script/software and that here will be a little more
> problematic to read e-mail through web interface (however, this could be
> solved, but searching through web IMAP won't be possible). And of
> course, this apllication should be available for different, also mobile,
> operating systems.
> So - is there some similar solution and if not - is there someone who
> would like to help developing such a solution?
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