According to Slashdot, Paypal has handed over to the FBI 1000 IP addresses involved in DDoSing it last year. That’s a lot of IP addresses. It’ll be interesting to see if much comes of it. I don’t know how long ISPs keep IP logs. It will depend on the ISP I guess but there may be some laws in place defining exact periods. I guess it’ll either be 6 months or 12, if it’s the former then they’ll be out of luck.
I imagine there are quite a lot of people getting quite worried now, probably people who signed up to Anonymous when they started getting so much news coverage(/advertising) without really understanding what they were doing and the legal implications. To some extent Anonymous relies on these people and gives them an inaccurate analysis of the risk they undertake, which is very wrong, but there we go. If you are one of those people, you were stupid but you already know that. Don’t panic, and don’t make it worse.
I am not a lawyer, I did a couple of computer law modules at uni, but here is my opinion (UK specific):
In the UK under the relevant legislation I believe you can plead guilty and get a mini-trial under a judge instead of with a jury. I might have made that up, but let’s assume I didn’t. If you are guilty then this is a safer option for you because there is a limit on the sentence that can be imposed (I think it’s 1 year jail time). Also, a judge should take into account your co-operation, and given that you aren’t a ring-leader and haven’t been involved since (hopefully), you might well avoid a custodial sentence.
Some common (exceedingly bad) advice is to nuke your hard disk. You absolutely must not do this. It is destruction of evidence or obstruction of justice or whatever we call it here, and they can charge you for that. It is easily possible to determine if a hard disk was wiped recently by the timestamps of the files, by how far back the operating system logs go, etc, and if yours was, it is almost an admission that you were doing something wrong and wanted to get rid of the evidence. They must already have some evidence if they’ve even got to the stage of arresting you, and that in conjunction with a zeroed hard disk will probably be enough. So they’ll probably still charge you with everything else anyway, and then charge you with destruction of evidence, which a judge will clobber you for because it looks like you’re trying to get one over on the system he’s supposed to be regulating.
Similarly, don’t bother encrypting everything. Withholding encryption keys is illegal.
If you get arrested, admit what you did when asked, deny anything you didn’t do, and talk to a lawyer as soon as possible. It is not necessarily preferable to refuse to co-operate outright until you have a lawyer, because the police might later try to infer you refused to talk because you were getting your story straight (I know of someone who claims this happened to them). It’s probably best to be open, but of course, don’t trust them; like anyone else, some members of the police will be honest people doing the best job they can, whereas others will be corrupt and will try to get you for anything they think they can to make themselves look more successful. You have to assume they are the latter, and be careful not to let them implicate you in anything you didn’t do.
Finally, ignore any advice from Anonymous because the leaders don’t have your interests at heart. And don’t worry about prison rape, that’s a strange American phenomenon/obsession.