"Den säkraste datorn är en som är avstängd"

- Det kommer alltid att finnas folk som försöker ta sig in i datorer, säger den internationella datasäkerhetsexperten Simon Janes, på besök i Sverige.

Här svarar han på läsarnas frågor om hackare, återskapning av raderade filer och hur man skyddar sig mot angrepp.

Simon Janes säger: Now I am here. You are welcome with questions about computer forensics.

Storvretakillen säger: Is it hard work??

Simon Janes säger: Yes it can be. It's not always drama and excitement. Sometimes it's a quesion of looking though hundrends of thousands of entries to find the information that you need.

haxxor säger: what kind of files are you mostly looking for?

Simon Janes säger: It depends on what type of investigation it is. More often the best evidence is not in a file, but in parts of the hard drive that both the user and the operating system has forgotten about.

el Bandito säger: Ok Ace. How long would it take for you to track me down to my current position ?

Simon Janes säger: It depends on what you've done wrong.

hasse säger: how easy is it for hackers to break a firewall (software)

Simon Janes säger: Statistics say that between 80 and 90 percent of serious computer incidents occur from within an organisation. So getting through a firewall is not necessarily an issue.

the spy säger: how can you recreate deleted files, can I do it if I delete a file by misstake?!

Simon Janes säger: Yes you can recreate a file. It depends whether you have the right tools and knowledge on how to recover it. It is often a question of finding it on the hard disk and reconstructing it as your file.

Christian.., säger: can you get hold of files on harddrives that has been formatted?

Simon Janes säger: Yes. When you format a hard drive it is only like taking away the index to a book. The pages are still there.

e säger: How can I make sure my deleted files can not be restored?

Simon Janes säger: To completely remove a file from my computer system is not necessarily as easy as it may seem. A file may reside on a hard drive in a number of different places and in different fragments. It is often these fragments that give the investigators the information that they need. You would need to use a very specialized tool and you would need the knowledge of how to use it.

Cade säger: Hey Simon! Umm i was just wondering, What organisation or company do you represent?

Simon Janes säger: Ibas Computer Forensics. We are a pan-European company that specialises in data recovery and computer forensics. We have offices across Europe and Asia, including Sweden.

Clara säger: What education do you have?

Where have you studied?

Simon Janes säger: I was a Scotland Yard detective for 22 years, where we investigated hackers, virus writers and other computer criminals, so I have learnt through experience.

salnik säger: The chat describes you as a "computer detective". Is that how you"d describe yourself?

Simon Janes säger: The word detective is often associated with the police. The work I do now is very different from the work at the police. But in essence we still conduct professional investigations - it's just not necessarily to do with crime.

Myran säger: What is the worst thing you've found in a computer?

Simon Janes säger: I suppose some of the more horrific pictures that can be found on the internet. Even after a career as a policeman some of the pictures can still be disturbing.

Rune säger: do you recommend anything else than a virus program and firewall to protect yourself from hackers?

Simon Janes säger: The amount of security you need on a computer is often proportionate to what it is you are trying to protect. Human nature being what it is, people will always break into computers. My advice would be to seek professional advice.

janne säger: Well Simon , is hard to trace information when its crypted ?

Simon Janes säger: The subject of encryption is a complex one. From a forensic point of view there are different ways and methodologies that we can apply that normally give us the evidence that we need.

kalle säger: what would you describe as the biggest security issues in todays computer-based society ?

Simon Janes säger: All information has a value. As we use computers more and more for business and electronic commerce, so the value of that information increases. It is the issues of intellectual property and copyright that I think is probably the fastest growing issue today.

gustav säger: the only thing happening when you delete something on your harddrive is that a little bit of the index are beeing deleted, so the information is still there. But there are lots of programs that can overwrite the information and makes it impossible to retrieve, what"s your opinion on that?

Simon Janes säger: Yes there are a number of these programs that exist. Some are better than others. But the last four or five occations that I have dealt with investigations where they have been used we have still found sufficient evidence or fragments of the file to prove the case.

Aldo säger: Do you have the skills to hack into an Internet bank if you wanted to?

Simon Janes säger: I don't know until I try, and I'm not going to.

sofia säger: What makes you so good ?

Simon Janes säger: Computer forensics require many skills, including technical and investigative. No one person can have all those skills, and I am the last person to pretend that I have. But what we do have is a team of mulit-skilled experts. Together it makes us better than the bad guy.

Xander säger: Could you get in to my computer from where you are now? How hard is it to get into to someones computer?

Simon Janes säger: I don't know until I try, and I"m not going to. It all depends on the level of security.

ingulf säger: is it possible for hackers to break a "real" firewall?

Simon Janes säger: It depends on what you mean by a real firewall, what firewall it is and how it is configured. A firewall is usually the strongest point of security. A majority of hackers will often look for the weakest point of security.

namn säger: do you have many enemies?

Simon Janes säger: Hopefully I have more friends.

bobdog säger: How to reach highest possible security? Do you recommend any Operating Systems? Physical or virtual firewalls, which is best?

Simon Janes säger: The safest computer is one that is not turned on. The choice of operating systems and firewalls depends on many circumstances.

NaNda säger: computer files exposed the ericsson spys... what did they found "Spy.txt?"

Simon Janes säger: You'd better ask the investigators.

Rune säger: how much money do you make?

Simon Janes säger: Never enough.

Thanks very much for your questions. They have certainly been varied. It's been a pleasure visiting Sweden. Moderator säger: Tack Simon Janes och alla chattare. Ett chattsammandrag finns på sajten inom kort.