From: nobody@hidden.net (Anonymous)
Date: Tue, 20 May 1997 11:21:57 +0800
To: cypherpunks@cyberpass.net
Subject: Remailer messages of variable length
Message-ID: <199705200305.UAA09291@jefferson.hidden.net>
MIME-Version: 1.0
Content-Type: text/plain


To complicate traffic analysis Sender can add a padding to his message
before encrypting it for some remailer in chain. So that the
message is shortened after decryption and stripping of pseudo headers.
It can be done with a dummy header lines:

##
Padding: fjx6zRURnnK1DV4CdL7gbHpnUiV1KbbRf5HatXiaD+ZPtH0 ...

Also, for a length increment a remailer may understand commands like:

##
Pad-length: 1K
Pad-encrypt-for: remailer@replay.com

It will then add the 'Padding:' header and re-encrypt the message with
the appropriate remailer's public key. The next remailer in chain will see
the padding and will try do decrypt the message twice...

If stealth crypto is used, a random padding can be simply attached to the
end of the message.

Also, the remailer by itself can decide to increase a message length to
cover some rare big messages.

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