Following the attacks of 11 September, the general public’s first instinctive reaction was to strongly criticize the lack of efficiency of the secret services, in particular American, who did not see anything coming despite their colossal infrastructure for tapping and filtering phone conversations, faxes and e-mails (viz. the considerable amount of money invested by the NSA in the famous Echelon program). Nonetheless, it seems that a number of clues were to be found on the Internet. And for this reason, FBI agents are still investigating the furthest corners of the web, looking for traces of those responsible for the attacks in the USA.
However, the method of investigation being used is extremely difficult to carry out, often unproductive and probably ill adapted to the dangers that come from the emerging type of "digital warfare".
The current method involves searching hard disk drives of computers that might have been used by the Islamists in hypothetical cyber cafés, or more frequently analyzing the millions of e-mails that pass through the different Internet Service Providers (ISP). Programs like "Carnivore" are used to monitor and filter these Internet-based transmissions.
This is only effective is very specific cases, notably where there is sufficiently reliable information to be able to say that a particular computer in a particular cyber café has been used or that information has transited via a particular ISP. Even when this information is available, the intercepted messages are often encrypted (PGP is one of the programs most commonly used). Worse still, messages are sometimes hidden inside otherwise anodyne images (using the principle of stenography).
The fight against cyber terrorism does not just involve identifying the guilty and understanding how they communicated with each other. Wire-tapping, espionage and counter-espionage systems have always existed, on and off the Internet. The question is not there. The method of action chosen by the Islamists is directly inspired by the model of the Internet and, as a result, is all the more terrifying.