Introduction[edit]

A nym server is: ^[1]

... a pseudonym server that furnishes an untraceable email address. The purpose of this server is to allow users to have usernames (pseudonyms) and send and receive messages without revealing their true identities. Even the nym server operators cannot trace a user's email address.

This arrangement means nym servers (and a network of anonymous remailers) send pseudonymous emails and forward the replies to the user's real email address. In order to use nym servers: ^[1]

• Registration is required with an available server located on the internet.
• A PGP key pair must be created and sent to the nym server, as well as the reply block for anonymous remailers in order to send a message to the creator's real email address for replies.

Rationale[edit]

Properly created nym server systems are considered relatively anonymous -- it is difficult to trace the nym server or identify the real email sender. ^[2] In addition, this configuration provides an uncensorable inbox that does not rely on a single service provider; this is beneficial in today's climate where a number of email services have abruptly shut down due to coercion or service restrictions (see Lavabit ^[archive] for a recent example). Further, it is unnecessary to risk browser-based logins in a webmail interface, thereby reducing the chance of connections being intercepted or poised by adversaries relying on specific selectors.

The following guide utilizes Zax-type nym servers ^{[archive] [3]} as they are infinitely more usable than the original GHIO-type servers which should be avoided at all costs (unless you enjoy hand-crafting reply-blocks ^[archive]). Readers who are unfamiliar with the term 'reply-block' should not be concerned because no manual configuration is necessary in these instructions.

To manage your nym, messages can be sent to the nym server via a SMTP server or even a personal email address (unrecommended, but still functional). Previously Whonix ™ strongly recommended the use of Mixmaster to communicate with nym servers, since they are commonly used together but are totally independent. Unfortunately this is no longer possible, as Mixmaster is dead upstream and has been permanently removed from Debian ^[archive].

Message Path[edit]

Table: Message Path Factors

Instructions[edit]

This guide uses mixnym.net, but the same steps equally apply to any other Zax-type nym server. For a selection of nym servers, see: Zax-type Nym Server List.

The examples below use the nym nym@mixnym.net -- adjust this text to match your nym choice and the domain name of the nym server.

Conventions[edit]

It is important to know which address should be used when sending messages to the nym server:

• config@mixnym.net: creation or configuration requests, to create and manage your nym
• send@mixnym.net: send requests, to send messages from your nym to other people
• url@mixnym.net: url requests, to retrieve an HTML page

For an overview of the process, seven primary steps apply:

1. Import the Nym Server Key
2. Prepare the Nym Request
3. Send Request to the Nym Server
4. Retrieve Messages from the Newsgroup
5. Decrypt Messages
6. Send Mail with Registered Nym
7. Reconfigure Nym

Import the Nym Server Key[edit]

A nym server's key is usually on their homepage. Follow these steps to import the key.

curl -o key.asc http://is-not-my.name/key.asc

gpg --keyid-format long --with-fingerprint key.asc

pub  4096R/0xFF4DB66014D0C447 2010-05-05 URL is-not-my.name (URL Retrieval address for Is-Not-My Nymserver) <url@is-not-my.name>
      Key fingerprint = 94F2 04C2 8BF0 0937 EFC8  5D1A FF4D B660 14D0 C447

gpg --import key.asc

gpg --keyserver keys.openpgp.org --recv-keys 94F204C28BF00937EFC85D1AFF4DB66014D0C447

gpg --keyserver keys.openpgp.org --search-keys config@mixnym.net

Prepare the Nym Request[edit]

Create a Key Pair[edit]

Create a new key pair for nym@mixnym.net.

gpg --gen-key

    Please select what kind of key you want:
       (1) RSA and RSA (default)
       (2) DSA and Elgamal
       (3) DSA (sign only)
       (4) RSA (sign only)
    Your selection? 1

    What keysize do you want? (2048) 4096

    Please specify how long the key should be valid.
             0 = key does not expire
          <n>  = key expires in n days
          <n>w = key expires in n weeks
          <n>m = key expires in n months
          <n>y = key expires in n years
    Key is valid for? (0) 6m

    Real name: John Doe
    Email address: nym@mixnym.net
    You selected this USER-ID:
        "nym@mixnym.net <nym@mixnym.net>"

    You need a Passphrase to protect your secret key.

    public and secret key created and signed.

Make sure to provide different information from the example above. Also note the nym expires when the key expires.

Export Public Key[edit]

To create a nym, its public key must be exported and sent to the nym server. In the following example, it will be copied to pubkey.txt.

gpg --armor --export nym@mixnym.net > pubkey.txt

Configure Additional Options[edit]

This step is only necessary if choosing to configure additional nym options, such as Subject Identification or Symmetric Encryption. For each option, prepend a line to the pubkey.txt file using the following format.

option: setting

Caps are unimportant in the option name, but are sensitive in the setting.

The nym server parameters specified here are optional. ^[5] They can be set immediately or changed in the future as detailed in the Reconfigure Nym section.

Table: Optional Nym Server Parameters

For a concrete example, to add the hSub passphrase panda, pubkey.txt should be edited as follows:

    hsub: panda

    -----BEGIN PGP PUBLIC KEY BLOCK-----
    <snipped>
    -----END PGP PUBLIC KEY BLOCK-----

More than one option line can be added to the request, but be aware that some options might create conflicts. For example, subject and hsub work differently, but are used for the same purpose -- only one of these options should be used at the same time.

Encrypt the Request[edit]

It is necessary to wrap pubkey.txt -- the message containing additional options and the public key -- to the nym server. The pubkey.txt file is the input for the following example and the encrypted file will be created as pubkey.txt.asc:

gpg --armor --encrypt --recipient config@mixnym.net pubkey.txt

It is safe to ignore the warning about encrypting to an "untrusted" key and just select y for yes.

Send Request to the Nym Server[edit]

Before sending the request, update the remailer keys first. It is enough to complete this procedure on a daily basis: ^[7]

    mixmaster

    u)pdate stats

    *

    pick remailer letter (optional)

    <space>

    q)uit

Send the encrypted file to the nym server with Mixmaster:

mixmaster --mail -l *,*,* -c 2 config@mixnym.net pubkey.txt.asc

Where:

• -l customizes the remailer chain length. The shorter the chain the faster the mail will be sent, thereby improving the chances of success. In this example, three random mixes are in use: *,*,*.
• -c sends copies of the message. In this example, 2 copies are sent.

If necessary, run Mixmaster from the command line and check the remailer chain list to see node availability and reliability statistics, then choose accordingly.

If all steps were followed correctly, the nym server will decrypt the message, extract your nym's email address from the supplied public key, then process it. Provided the nym is not reserved or already taken, a confirmation message will be received from the nym server, encrypted to your nym's key.

Note that the protection provided by Mixmaster is of little importance here because everything is done behind Tor. ^[8]

Retrieve Messages from the Newsgroup[edit]

Zax-type nym servers deliver messages to nyms via the alt.anonymous.messages Usenet group (a.a.m). Anyone can access these messages, but only the nyms can decrypt them by using their private keys.

As explained earlier, messages can be configured to be identified by subject. If a form of subject identification was set up from the previous section, then refer to the Use aam2mail to Fetch Replies section.

If subject identification was not configured but is desirable, then a configuration message must be sent to stipulate a method of subject identification. An example can be found in the Reconfigure Nym section.

If no form of subject identification is desired, then the default method is to download and attempt to decrypt every message posted on the Newsgroup. If it works, then the message was sent to your nym.

Use aam2mail to Fetch Replies[edit]

sudo apt install git

git clone https://github.com/crooks/aam2mail

cd aam2mail

sudo python setup.py install

mkdir ~/aam2mail/etc

echo 'panda' >> aam2mail/etc/subject_hsub

echo 'nntp.aioe.org' >> aam2mail/etc/servers

aam2mail --start

aam2mail --restart

Decrypt Messages[edit]

With the message saved to a file, decrypt it as follows.

gpg --decrypt file

If successful, the plaintext of the message your nym received should be visible.

Congratulations on registering your first nym! Now it can be used for sending messages.

Send Mail with Registered Nym[edit]

To send messages to other people, the steps are very similar to those used previously for creation and configuration.

To: recipient@domain
Subject: Example

This is an example

gpg --armor --encrypt --sign --recipient send@mixnym.net message.txt

mixmaster --mail -l *,*,* send@mixnym.net message.txt

Take note that copies of the message were not sent on this occasion. This was advisable for the creation step, because after receiving the first one the server would ignore the others. In this case of sending mail, if copies are sent the server will send all of them to the recipient.

Reconfigure Nym[edit]

hsub: passphrase

gpg --armor --encrypt --sign --recipient config@mixnym.net option.txt

mixmaster --mail -l *,*,* config@mixnym.net option.txt.asc

Important Notes[edit]

End-to-End Encryption[edit]

The encryption layers discussed in this wiki entry will only protect data between the nym and the server. It is recommended that another form of end-to-end encryption (another layer) is added between you and the recipient, for example by encrypting the body of the message first, and then encrypting to the server's key.

Bear in mind the headers cannot be encrypted, so an end-to-end encrypted message would appear similar to the example below.

    To: recipient@domain
    Subject: Subject

    -----BEGIN PGP MESSAGE-----
    <snipped>
    -----END PGP MESSAGE-----

After this step, users would then encrypt to the nym server so it would appear like the example below.

    To: send@server

    -----BEGIN PGP MESSAGE-----
    <snipped>
    -----END PGP MESSAGE-----

Message Ordering[edit]

Due to Mixmaster's latency, it is possible for messages to arrive out of order. For instance, later messages might arrive earlier than the creation message. If no responses are received, it is necessary to send them again once the nym is created.

Multiple Nyms[edit]

If more than one nym is used, you must remember to choose which nym will sign the message, or always use the same nym to send the messages, and consequently only these messages will be accepted. As noted earlier, the only message accepted without a signature is the creation message.

To specify the nym that will sign the message, use the --local-user flag.

gpg --armor --encrypt --sign --recipient send@server --local-user nym@server message.txt

Public Mailbox[edit]

When someone sends a message to your nym, the server will receive it, encrypt to the nym and post it on a.a.m so it can be retrieved. The Newsgroup acts as a public mailbox -- everybody can see and download the messages but only the intended recipient (your nym) can decrypt it.

Zax-type Nym Server List[edit]

Although the reference is dated, active Zax-type nym servers in 2019 include: ^[9]

• nymphet.paranoici.org
• mixnym.net ^[archive]
• https://www.cotse.net/ ^[archive]

Public/Open News Servers[edit]

• news.dizum.net ^[10]
• https://news.aioe.org/ ^{[archive] [11]}
• news.mixmin.net ^[11]

Other Useful Topics[edit]

• The default Mixmaster editor can be changed to something more usable than vi with the following steps. ^[12]

Whonix ™ KDE:

sudo echo 'export EDITOR=kwrite' >> ~/.bashrc

Whonix ™ XFCE:

sudo echo 'export EDITOR=mousepad' >> ~/.bashrc

Logout and then log back in again for changes to take effect.

• What happens if you register a nym that is already taken?

A message will be received in a.a.m that it is already taken. ^[13]

Development Notes[edit]

• Explore whether aam2mail ^[14] can be shipped as a stand-alone python utility for hsub management.
• Further reading: the Mixnym.net key expired but Zax fixed the problem. ^[15]

See Also[edit]

• E-Mail
• Remailer

Sources[edit]

This wiki entry is based on Zax's help ^[archive] guides ^[archive] on Mixnym.net, which is also archived ^[archive] here ^[archive]. Appreciation is also expressed to the Nymphemeral ^[archive] developer, ^[16] Felipe Dau, for helping with these instructions.

Footnotes[edit]

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