Re: end-to-end encryption

2018-05-16 Thread Gandalf Corvotempesta
Il giorno mer 16 mag 2018 alle ore 12:02 Aki Tuomi 
ha scritto:
> To be strict, 'end to end' would mean that the SENDER would encrypt it
> on his station, and RECEIVER would only decrypt it on his station.
> Everything else is not end-to-end =)

Yes, of course, but this solution with GPG where dovecot is able to encrypt
mails with GPG key
will increase the overall security, but still allows to read all email
(just before the encryption) with
some malwares and so on.


Re: end-to-end encryption

2018-05-16 Thread Jochen Bern
On 05/16/2018 12:01 PM, Aki Tuomi wrote:
> On 16.05.2018 12:56, Jochen Bern wrote:
>> Considering the keywords "dovecot" and "sieve", that would still not be
>> "end to end" and not even "MSA to MX"(-ish) but merely "encrypted
>> storage upon/after final delivery", wouldn't it ... ?
> 
> To be strict, 'end to end' would mean that the SENDER would encrypt it
> on his station, and RECEIVER would only decrypt it on his station.
> Everything else is not end-to-end =)

Yes. Hence my ad-hoc "MSA to MX" terminology for the middle ground that
sysad-me can achieve *without* continued user enthusi^H^H^H^H^H^H^H
cooperation. :-}

Regards,
-- 
Jochen Bern
Systemingenieur

www.binect.de
www.facebook.de/binect



smime.p7s
Description: S/MIME Cryptographic Signature


Re: end-to-end encryption

2018-05-16 Thread Aki Tuomi


On 16.05.2018 12:56, Jochen Bern wrote:
> On 05/16/2018 06:07 AM, Aki Tuomi wrote:
>>> On 15 May 2018 at 22:43 Gandalf Corvotempesta 
>>>  wrote:
>>> Is possible to implement and end-to-end encryption with dovecot, where
>>> server-side there is no private key to decrypt messages?
>> You could probably automate this with sieve and e.g. GnuPG, which would mean
>> that all your mails are encrypted without server having key to decrypt this.
> Considering the keywords "dovecot" and "sieve", that would still not be
> "end to end" and not even "MSA to MX"(-ish) but merely "encrypted
> storage upon/after final delivery", wouldn't it ... ?
>
> FWIW, for auto-encrypting someplace near the MSA, I've used the "GPGPit"
> tool that's available on the web (and that I've made into an "SMIMEit"
> myself). The nontrivial problem with that is to retrieve recipients'
> pubkeys in an even remotely trustworthy manner, of course.
>
> Regards,

To be strict, 'end to end' would mean that the SENDER would encrypt it
on his station, and RECEIVER would only decrypt it on his station.
Everything else is not end-to-end =)

Aki


Re: Re: end-to-end encryption

2018-05-16 Thread Jochen Bern
On 05/16/2018 06:07 AM, Aki Tuomi wrote:
>> On 15 May 2018 at 22:43 Gandalf Corvotempesta 
>>  wrote:
>> Is possible to implement and end-to-end encryption with dovecot, where
>> server-side there is no private key to decrypt messages?
> 
> You could probably automate this with sieve and e.g. GnuPG, which would mean
> that all your mails are encrypted without server having key to decrypt this.

Considering the keywords "dovecot" and "sieve", that would still not be
"end to end" and not even "MSA to MX"(-ish) but merely "encrypted
storage upon/after final delivery", wouldn't it ... ?

FWIW, for auto-encrypting someplace near the MSA, I've used the "GPGPit"
tool that's available on the web (and that I've made into an "SMIMEit"
myself). The nontrivial problem with that is to retrieve recipients'
pubkeys in an even remotely trustworthy manner, of course.

Regards,
-- 
Jochen Bern
Systemingenieur

www.binect.de
www.facebook.de/binect



smime.p7s
Description: S/MIME Cryptographic Signature


Re: end-to-end encryption

2018-05-16 Thread tobisworld
Yes the server need to know the pubKey for encryption and the client
need access to the privKey to decrypt.
The correct pubKey is determined from gpg based on the rcpt address

Cheers

tobi

Am 16.05.2018 um 11:30 schrieb Gandalf Corvotempesta:
> Il giorno mer 16 mag 2018 alle ore 11:19  ha scritto:
>> I personally use gpgit https://github.com/EtiennePerot/gpgit
>> Which does the encryption of messages. Then I use a sieve script which
>> calls gpgit for every msg and encrypts before saving into mailbox
> 
> If I understood properly, for this to work, a public key must be stored on
> server,
> so that every message is encrypted. Then, on each MUA, the private key must
> be
> present, so that each MUA is able to decrypt the encrypted message, right ?
> 


Re: end-to-end encryption

2018-05-16 Thread Gandalf Corvotempesta
Il giorno mer 16 mag 2018 alle ore 11:19  ha scritto:
> I personally use gpgit https://github.com/EtiennePerot/gpgit
> Which does the encryption of messages. Then I use a sieve script which
> calls gpgit for every msg and encrypts before saving into mailbox

If I understood properly, for this to work, a public key must be stored on
server,
so that every message is encrypted. Then, on each MUA, the private key must
be
present, so that each MUA is able to decrypt the encrypted message, right ?


Re: end-to-end encryption

2018-05-16 Thread tobisworld
Hi

I personally use gpgit https://github.com/EtiennePerot/gpgit
Which does the encryption of messages. Then I use a sieve script which
calls gpgit for every msg and encrypts before saving into mailbox

Cheers

tobi

Am 16.05.2018 um 10:24 schrieb Gandalf Corvotempesta:
> Il giorno mer 16 mag 2018 alle ore 06:09 Aki Tuomi 
> ha scritto:
>> You could probably automate this with sieve and e.g. GnuPG, which would
> mean that all your mails are encrypted without server having key to decrypt
> this.
> 
> Any guide or sample to look for ?
> 


Re: end-to-end encryption

2018-05-16 Thread Gandalf Corvotempesta
Il giorno mer 16 mag 2018 alle ore 06:09 Aki Tuomi 
ha scritto:
> You could probably automate this with sieve and e.g. GnuPG, which would
mean that all your mails are encrypted without server having key to decrypt
this.

Any guide or sample to look for ?


Re: end-to-end encryption

2018-05-15 Thread Steffen Kaiser

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Hash: SHA1

On Tue, 15 May 2018, Gandalf Corvotempesta wrote:


I was looking at protonmail.com
Is possible to implement and end-to-end encryption with dovecot, where
server-side there is no private key to decrypt messages?


Maybe the term "end-to-end encryption" has changed, but usually that 
means that clients are the "end". Hence, there are no keys on the server. 
There are some approaches to automatic key discovery and hosting with 
GnuPG's WKD / WKS.



If I understood properly, on protonmail the private key is encrypted with
user's password, so that only an user is able to decrypt the mailbox.


When the encryption takes place on the server, the server admin is able to 
tinker the process, hence, this is no end-to-end. But, read Aki's fine 
answer about this.


- -- 
Steffen Kaiser

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Re: end-to-end encryption

2018-05-15 Thread Aki Tuomi

> On 15 May 2018 at 22:43 Gandalf Corvotempesta 
>  wrote:
> 
> 
> Hi to all
> I was looking at protonmail.com
> Is possible to implement and end-to-end encryption with dovecot, where
> server-side there is no private key to decrypt messages?
> 

You could probably automate this with sieve and e.g. GnuPG, which would mean 
that all your mails are encrypted without server having key to decrypt this.

> If I understood properly, on protonmail the private key is encrypted with
> user's password, so that only an user is able to decrypt the mailbox.
> 
> Anything similiar ?

In this case, the server *does* have the private key, even if it's encrypted... 
=)

Dovecot's mail crypt plugin can achieve *similar* thing with 

mail_crypt_private_password=%{password} (see 
https://wiki.dovecot.org/Plugins/MailCrypt)

But this requires quite good planning, esp. if you are hosting mails, since 
there is currently no DR feature in dovecot. If you decide to use mail crypt 
plugin, set it up with private key password, and lose the password, then the 
mails really are gone.

Also worth noting is that, currently, dovecot does not encrypt indexes, which 
can contain information about your mails.

Aki


end-to-end encryption

2018-05-15 Thread Gandalf Corvotempesta
Hi to all
I was looking at protonmail.com
Is possible to implement and end-to-end encryption with dovecot, where
server-side there is no private key to decrypt messages?

If I understood properly, on protonmail the private key is encrypted with
user's password, so that only an user is able to decrypt the mailbox.

Anything similiar ?