This is an example Nym Book which demonstrates a high-security nym account. Each pair of reply-blocks demonstrates a different set of techniques, as detailed below. If you are new to nym accounts, you should first practice setting up and using a lesser nym account, such as that produced by the Quick Nym example.
High-security nym accounts require more maintenence than simpler accounts. You may also have to experiment with different remailers to see which work reliability. The purpose of this Nym Book is to demonstrate the techiques. You may choose to use only a portion of these in your own reply-blocks for some added security while still maintaining reliability.
Note: For good security and reliability, 1 to 3 reply-blocks are recommended. Using more may make traffic analysis easier.
When running these reply-blocks, you may get insufficient AUTO remailer warnings because of the additional capability requirements. In that case you will need to hand-pick your remailers or reduce the criteria. Be sure to select Edit|Replace Passphrases and also change any Encrypt-Subject passphrases (if applicable) before running this book,
Notice that Options|Remix Compliant is checked. This causes JBN to select AUTO remailers such that your messages are transparently remixed at every stage.
Blocks 1 and 2:
These reply-blocks are designed to be used as a pair, both terminating at the same email address. Using two different probability variables, together they generate slightly more mail than is actually sent to your account (which makes traffic analysis more difficult). (Block 1 uses no explicit variable, which means it has a probability = 1, or it generates mail every time. Block 2 only generates mail for 2 out of every ten messages. So on average, you will receive 12 messages for every ten sent to your account.) Their internal design is similar. In practice you may wish to use explicit remailers instead of random remailers, and make both blocks use the same remailers, or at least terminate with the same remailer.
Max-Size: 15 at the top of this reply-block specifies that only messages under 15K will make it through. This nym account is fixedsize, so 15 is appropriate.) The Max-Size setting prevents an attacker from tracking your reply-block by sending large messages with it.
Max-Count: 40 means that if more than 40 messages are sent on any given day, the rest of the messages will be deleted. This value may be adjusted depending on the amount of mail you receive. Keep in mind that the nym-server splits large messages into multiple pieces with fixedsize accounts.
The Max-Date directive at the bottom, which applies to all the reply-blocks of this nym account, should be set a few months ahead. After this date mail will be deleted by the max remailers. This prevents someone from archiving your reply-block and using it at some time in the future. If you wish to use different Max-Date directives for each reply-block, leave this setting blank and set the directives yourself at one or more remailers in each chain.
NYM-SERVER [nym, ek, latent] uses latent and ek. Add Remix-To if your nym-server supports it. (At the time of this writing only Redneck does.)
AUTO1 [ek, ekx, latent] uses ek and ekx, so that your message is encrypted three times with different random passphrases using CAST, 3DES, and IDEA, respectively. (If you're not using PGP 5/6, remove the 3DES and CAST encryption or you won't be able to decrypt your mail.) If decryption time is an issue, use just one. (See the Passphrase FAQ for a comparison.)
AUTO2 [ek, ext, rhop, remix, latent] specifies Remix-To, Encrypt-To, and Anon-To directives (ext). (To _require_ remix, uncheck the Encrypt-To and Anon-To boxes. By having all three checked, the message will get through even if the remailer has remix disabled.) This stage uses Rand-Hop: 2r, which means the remailer will chain to between one and two additional (mixmaster) remailers to reach AUTO3.
AUTO3 [ek, latent] delivers the final message.
Blocks 3 and 4:
These reply-blocks terminate at alt.anonymous.messages via a mail2news gateway. These blocks are also designed as a pair which together produce slightly more mail than is actually sent to the account. This makes it more difficult to determine which nym account the messages belong to.
NYM-SERVER [nym, ek, latent] uses latent and ek. Add Remix-To if your nym-server supports it. (At the time of this writing only Redneck does.)
AUTO1 [ek, ekx, latent, remix] uses ek and ekx, so that your message is encrypted three times with different random passphrases using CAST, 3DES, and IDEA, respectively. (If you're not using PGP 5/6, remove the 3DES and CAST encryption or you won't be able to decrypt your mail.) If decryption time is an issue, use just one. (See the Passphrase FAQ for a comparison.) It also specifies only a Remix-To directive, meaning that if the remailer has remix disabled, the message is deleted. (To be more lenient, also check the Encrypt-To box.)
AUTO2 [ek, esub, latent] encrypts the message with ek and encrypts the subject with Encrypt-Subject. (To see the directive, double-click on the remailer to open the remailer editor.) [YOU SHOULD CHANGE the Encrypt-Subject passphrase before using this reply-block!] This remailer sends the message to a mail2news gateway.
Blocks 5 and 6:
These two reply-blocks have probability variables which add to 1.0, which means that any given message will travel through one or the other, but never both. These reply-blocks are intended for a nym account which recieves larger messages. It is intended that fixedsize be disabled when using these reply-blocks. (Large messages sent to a fixedsize account tend to disable it because the nym-server not only limits the amount of mail, but also the number of messages.)
It is difficult to cloak large messages because their size makes them more easily identified. This reply-block uses a combination of remix and inflation to help the trail get lost. If your messages are very large, you may wish to disable remix by checking only Encrypt-To at each remailer. This will improve reliability but decrease security. You may also request that the sender split the large messages before sending them to you. (If they use JBN2 it can do this automatically, as can most MIME email apps.)
Although these reply-blocks show AUTO remailers, in actual usage you must hand-pick your remailers to insure they can handle the message size you intend to receive. (Consult the klen capability.)
Notice that these reply-blocks use long latent times. With large messages, use the longest random latent times you can tolerate. (Other people will be sending large messages occassionally too, so the increased time allows your messages to be covered by other large traffic.)
NYM-SERVER [ek and latent] This is a good place to use remix IF the nym-server supports it.
AUTO1 [inflt, rhop, remix, latent] inflates the message with up to 70K. Note that it does NOT encrypt the message. The message is already encrypted by the remix, and by not encrypting the inflation, the next remailer can remove it. A Remix-To directive is added exclusively. (If the remailer has remix disabled, the message is deleted.) This means that between AUTO1 and AUTO2, the message is broken into Mixmaster packets. There is also a Rand-Hop: 3r directive, so each packet takes a different route through between 1 and 3 randomly chosen remailers.
AUTO2 [inflt, cut, ekx, latent, rhop] first removes the 70Kr of inflation using a Cutmarks directive. It then adds up to 30K of inflation, and encrypts the message with both 3DES and IDEA. It then remails the message through between one and two random remailers. Remix-To is exclusively specified so each packet takes a different route.
AUTO3 [inflt, ek, latent] inflates the message by up to an additional 20K, encrypts it, and sends it to the final address after latency.
Notice that block 6 is similar but uses different remailers, latent times, and inflation values.
FOR GREATER SECURITY: Use longer chains of remailers and greater latency. If your nym-server supports remix, use Remix-To at the nym-server. (At the time of this writing, nym.alias.net does not support remix, Redneck does.)
