Anonymous Servers - Accessing nym account keys

Author

Accessing nym account keys

Christian Danner

2006-11-22, 7:12 pm

Hi all!

Why isn't it possible to get public keys of nym accounts by mail, e.g.
requested through another nym account?

They only can be retrieved by finger, at best secured by a short Tor
router chain, though such a task deserves more security than the
download of a server key or an alias list, as it reveals potential
communication partners. Wouldn't it be better to interpret a message
sent to a nym alias which is preceded by a token like 'key-'
('key-jdoe@nym.panta-rhei.eu.org') as a request of the respective
public key and then return those data?

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

StealthMonger

2006-11-23, 7:14 am

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Christian Danner <---@---.---> writes:

> Why isn't it possible to get public keys of nym accounts by mail,

It is. Use a web-to-mail gateway and a URL that invokes finger.
Details at http://www.expita.com/howto2.html#finger, which is part of
"G.E.Boyd's How to Do Just About Anything by E-mail". A currently
operative web-to-mail gateway is agora@dna.affrc.go.jp. A reliable
URL used to be http://www.mit.edu:8001/finger?user@domain.com. I
don't know whether this has now gone the way of lcs (down), but Boyd
provides a long (but old) list of alternatives.

> ... such a task deserves more security than the download of a server
> key or an alias list, as it reveals potential communication
> partners.

Agreed. Perceptive of you.

--

Use stealthmail: Scripts to hide whether you're doing email, or when,
or with whom. Available at http://stealthsuite.afflictions.org.

-- StealthMonger

<StealthMonger@nym.panta-rhei.eu.org>
<StealthMonger@nym.alias.net>
<StealthMonger@hod.aarg.net>

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Thomas J. Boschloo

2006-11-23, 7:14 am

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Christian Danner wrote:
> Hi all!
>
> Why isn't it possible to get public keys of nym accounts by mail, e.g.
> requested through another nym account?

Nym servers protect the identity of the nym user. Likewise your nym
protects the world from knowing who your real identity is.

There is nothing wrong with requesting the public key of another nym
server user in a non-automatic way. Some nym users even don't have their
key available! (-fingerkey). I once was using one secret key to decrypt
the messages of two nyms and I didn't want to world to know (hint: one
of those keys was the key with which I will sign this message)

Plus, if you know the person from usenet and he signs his messages, you
have plausible deniability that you just use the key for verifying her
messages (which is everso important in anonymous newsgroups like this)

So I say let it be this way and concentrate on Mixminion where the same
problem might arise.

hth,
Thomas
- --
Someone according to Willem F. de Jonge: "There are depths."
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Christian Danner

2006-11-24, 7:13 pm

Hi Thomas!

Thomas J. Boschloo wrote:

>
>Nym servers protect the identity of the nym user. Likewise your nym
>protects the world from knowing who your real identity is.

Both true - as far as we know / hope. But I don't quite understand
what this has to do with the offering of a nym's public key resp. the
optimum transmission method.

>There is nothing wrong with requesting the public key of another nym
>server user in a non-automatic way. Some nym users even don't have their
>key available! (-fingerkey).

I haven't proposed to make the nym server ignore the 'fingerkey'
settings. Of course, if a nym user for whatever reason - and I'm not
aware of even one - doesn't want her/his public key to be fingered, a
request by mail mustn't succeed either.

> I once was using one secret key to decrypt
>the messages of two nyms and I didn't want to world to know (hint: one
>of those keys was the key with which I will sign this message)

This really can't be called standard behaviour, right?

>Plus, if you know the person from usenet and he signs his messages, you
>have plausible deniability that you just use the key for verifying her
>messages (which is everso important in anonymous newsgroups like this)

An example: In a newsgroup you have a discussion with someone who
posts through a nym as you do, which usually shows, that both of you
have no objections to a direct mail contact. Now you have some
non-public information for your interlocutor. If you send it as plain
text it can be read by everyone on its way from your to her/his nym
server. So it has to be PK encrypted. But how to get the key of the
respective nym account? Best would be to let your nym, which will
later on anyway be recognizable as the communication partner, request
the data. But fact is, you've established a surefire anonymity
environment and aren't able to use it for such a critical purpose,
being forced to set up Tor and retrieve the data with finger through a
short real-time chain instead. That lacks both security and usability!

BTW, who can tell how to get nym keys from hod, which AFAICS doesn't
even run a finger service?

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

Christian Danner

2006-11-24, 7:13 pm

Hi!

StealthMonger wrote:

>
>It is. Use a web-to-mail gateway and a URL that invokes finger.
>Details at http://www.expita.com/howto2.html#finger, which is part of
>"G.E.Boyd's How to Do Just About Anything by E-mail". A currently
>operative web-to-mail gateway is agora@dna.affrc.go.jp. A reliable
>URL used to be http://www.mit.edu:8001/finger?user@domain.com. I
>don't know whether this has now gone the way of lcs (down), but Boyd
>provides a long (but old) list of alternatives.

Not the solution I had in mind, but a valuable alternative, which
unfortunately depends on further services. 8 of the mentioned finger
gateways are still on duty, so getting nym keys this way via a nym
account shouldn't be a big deal either. Nevertheless up to now I only
got replies like

The document requested
http://eup.k12.mi.us/cgi-bin/finger...nta-rhei.eu.org
is empty.

from Agora.

Interesting website BTW, which shows how to use a nym account in the
way of a Swiss army knife. Worth to be linked.

>
>Agreed. Perceptive of you.

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

Thomas J. Boschloo

2006-11-24, 7:13 pm

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Christian Danner wrote:
> Hi Thomas!
>
> Thomas J. Boschloo wrote:
>
>
> Both true - as far as we know / hope. But I don't quite understand
> what this has to do with the offering of a nym's public key resp. the
> optimum transmission method.

The first communication is never encrypted. Even with Ephemeral keying!
IOW, the first message between you doesn't need to be encrypted. And
this message can contain the key of the sender.

Alice knows she is communicating with Bob, who has send her his key.
Bob knows he is communicating with Alice who he has send his key to.

Bob can send his key using mixmaster so Alice doesn't know his real
e-mail address.

After that Alice (if she is still interested in contact with Bob, you
know how girls are) can send Bob her key.

Public keys are public. There is no need to encrypt or sign them. Trust
is harder, that I admit, but trust won't be solved by anonymizing your
key requests.

Thomas
- --
Someone according to Willem F. de Jonge: "There are depths."
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BiKiKii Admin

2006-11-24, 7:13 pm

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On 24 Nov 2006, Christian Danner wrote:

>An example: In a newsgroup you have a discussion with someone who
>posts through a nym as you do, which usually shows, that both of you
>have no objections to a direct mail contact. Now you have some
>non-public information for your interlocutor. If you send it as plain
>text it can be read by everyone on its way from your to her/his nym
>server. So it has to be PK encrypted. But how to get the key of the
>respective nym account?
>

Craft the message as PK encrypted to interlocutor's nymserver send@... key.
The only cleartext is whithin interlocutor's nymserver environment.

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Christian Danner

2006-11-26, 7:13 am

Hi Thomas

Thomas J. Boschloo wrote:

>The first communication is never encrypted. Even with Ephemeral keying!
>IOW, the first message between you doesn't need to be encrypted. And
>this message can contain the key of the sender.

You have something like 'Here's my key. Please send my yours. Then
I'll tell you what this is about.' in mind? Most of us wouldn't lift a
finger without being acquainted with the motives of the sender right
from the beginning, if only to block spammers.

>Alice knows she is communicating with Bob, who has send her his key.
>Bob knows he is communicating with Alice who he has send his key to.
>
>Bob can send his key using mixmaster so Alice doesn't know his real
>e-mail address.
>
>After that Alice (if she is still interested in contact with Bob, you
>know how girls are) can send Bob her key.

You're right, it might be hard to keep her interested with all this
back and forth ;-) I wouldn't call that a promising opening of a
private conversation.

>Public keys are public. There is no need to encrypt or sign them. Trust
>is harder, that I admit, but trust won't be solved by anonymizing your
>key requests.

For an adversary usually the recognition of (potential) communication
partners is way superior to the knowledge of the transferred data. So
IMHO the anonymity of key retrievals is mandatory.

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

Christian Danner

2006-11-26, 7:13 am

Hi!

BiKiKii Admin wrote:

>
>Craft the message as PK encrypted to interlocutor's nymserver send@... key.

Are you sure that messages encrypted with the nym server key of the
recipient are decrypted before being forwarded to the reply chain?
AFAIK that's not the case.

>The only cleartext is whithin interlocutor's nymserver environment.

Even if so, I would prefer an end-to-end encryption right from the
start.

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

BiKiKii Admin

2006-11-26, 1:12 pm

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On 26 Nov 2006, Christian Danner wrote:
>BiKiKii Admin wrote:
>
>
>Are you sure that messages encrypted with the nym server key of the
>recipient are decrypted before being forwarded to the reply chain?
>AFAIK that's not the case.
>
>

Here is example onion diagram:

Anon-To: remailer_1@foo.com

+---[4]{Encrypted to Remailer_1}---
|
| Anon-To: remailer_2@bar.com
|
| +---[3]{Encrypted to Remailer_2}---
| |
| | Anon-To: remailer_3@foobar.com
| |
| | +---[2]{Encrypted to Remailer_3}---
| | |
| | | To: send@nym.example.com
| | |
| | | +---[1]-{Encrypted to Nymserver}---
| | | |
| | | | To: abc@nym.example.com
| | | |
| | | | +---[0]----------------------------
| | | | |
| | | | | {Cleartext Message}
| | | | |
| | | | +----------------------------------
| | | +----------------------------------
| | +----------------------------------
| +----------------------------------
+----------------------------------

Why do your References headers get filled with whitespace?

Ciao!

BiKiKii

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Christian Danner

2006-11-27, 1:15 am

Hi!

BiKiKii Admin wrote:

>On 26 Nov 2006, Christian Danner wrote:
>
>
>Here is example onion diagram:
>
> Anon-To: remailer_1@foo.com
>
> +---[4]{Encrypted to Remailer_1}---
> |
> | Anon-To: remailer_2@bar.com
> |
> | +---[3]{Encrypted to Remailer_2}---
> | |
> | | Anon-To: remailer_3@foobar.com
> | |
> | | +---[2]{Encrypted to Remailer_3}---
> | | |
> | | | To: send@nym.example.com
> | | |
> | | | +---[1]-{Encrypted to Nymserver}---
> | | | |
> | | | | To: abc@nym.example.com
> | | | |
> | | | | +---[0]----------------------------
> | | | | |
> | | | | | {Cleartext Message}
> | | | | |
> | | | | +----------------------------------
> | | | +----------------------------------
> | | +----------------------------------
> | +----------------------------------
> +----------------------------------

(Un)fortunately there is more than one nym server, so IMHO the
strategy you recommend is only applicable in the special case of both
using the same server. A nym server discards messages in the 'send'
mailbox if the sender isn't owner of one of its nym accounts, verified
by the signature.

>Why do your References headers get filled with whitespace?

Thanks for the hint!

My first message in this subthread (before Mixmaster processing):

References: <SRA3RQXN39043.5638194444@anonymous.poster>
<45659196$0$27627$847b8a76@dreader15>

and later on received from the ng:

References: <SRA3RQXN39043.5638194444@anonymous.poster>
<45659196$0$27627$847b8a76@dreader15>

The spaces have probably been added by Dingo.

With my latest message OmniMix transferred

References: <SRA3RQXN39043.5638194444@anonymous.poster>
<45659196$0$27627$847b8a76@dreader15>
<XVPKPXK739045.4469328704@anonymous.poster>
<200611241108197709@bikikii.ath.cx>

without any modification to Mixmaster. Nothing unusual besides the 8
spaces after the first reference, taken over from the previous
message. I don't know where the argument got trimmed to

References: <SRA3RQXN39043.5638194444@anonymous.poster>
<45659196$0$276Q
<200611241108197709@bikikii.ath.cx>

I found two message of your own and some others with 'References'
headers crippled in a similar manner:

Message-ID: <DQ0AI6PN39001.7919560185@twistycreek.com>
References: <SRA3RQXN39043.5638194444@anonymous.poster>
<45659196$0$276Q
<200611241108197709@bikikii.ath.cx>

Message-ID: <CJ812V6S38986.8670138889@anonymous.poster>
References: <2c0c58bebd78da6b816987b210060211@dizum.com>
<1K0ORU6738936.64013888Q
<20060926210442.685$l3@newsreader.com>

So AFAICS there's nothing wrong with OmniMix (besides not reducing the
separators to one single space). It seems to be a problem at the exit.

Kind regards

Christian
--
OmniMix .. protect your privacy
http://www.danner-net.de/om.htm

BiKiKii Admin

2006-11-28, 1:13 pm

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On 27 Nov 2006, Christian Danner wrote:

>(Un)fortunately there is more than one nym server, so IMHO the
>strategy you recommend is only applicable in the special case of both
>using the same server. A nym server discards messages in the 'send'
>mailbox if the sender isn't owner of one of its nym accounts, verified
>by the signature.
>

Yes you are correct.

Ciao!

BiKiKii

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