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 JAP and Crime Prevention
Log Files at the Anonymization Service
Providers of telecommunications services are required by law in Germany to retain already-obtained data for the purposes of crime prevention.
Retro-active Exposure of Connections through the Mix Cascades
A retro-active exposure is close to impossible. If someone wanted to uncover a certain connection after the fact, he would have to record all incoming and outgoing messages from all mixes in a cascade and present them for de-anonymization. This only makes sense so long the public key of a mix is valid. After a key change, not even the mix itself can decrypt old messages, since the private key is destroyed. This is not yet implemented in the current version, but even the mix operator himself cannot access the key that is temporarily stored in memory. How often the key is changed depends on the mix operator. In the final system, this could occur as often as every few hours.
Note: The German Telecommunications Act might require some Mixes to retain traffic data which could be used to easy retro-active exposure.
Surveillance of Future Connections through the Mix Cascades
Surveillance of future connections requires that every mix in a cascade record the incoming-outgoing relationship of a certain message online and in realtime. The connection to be exposed would be marked. The message could then be de-anonymized with the cooperation of all mixes. The marking of a message would have to be recognizable to all mixes involved in the surveillance. This functions similarly to trapping a phone line in the standard telephone network. It would thus be possible to log access to a certain website with this method.
The current version of the mix software contains a crime prevention function that allows this method. The surveillance of a connection requires the cooperation of all mix operators in a mix cascade and their activation of this function.
Currently, a privacy-friendly surveillance method is being developed.
AN.ON Project's Experiences in the Area of Crime Prevention
In 2006, there has been only one single surveillance court order to single Mix operators. A few exactly specified
web addresses were affected. The observation has been stopped after the court order expired (one month).
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Restrictions for the Dresden (JAP) anonymisation servers
After careful consideration we have decided to restrict the size of downloads over the Dresden (JAP) mixes a little. The reason is to allow a more fair use of scarce resources of our servers especially for users who simply want to surf the Web. more...
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