unforum

[Misroi]

If the password is "PXCNo251", expect riots.

[hairysocks]

[David-A]

Yes.

We are trying all key combinations made up from characters 0-9, A-Z and a-z.

See a previous post for the answer to why this is a VERY safe/sensible approach.

[Basically we have 62 characters currently, the problem is adding an additional, say, 6 for the basic punctuation doesn't make the search 10% bigger. In fact it would make it whole orders of magnitude bigger. And it would take years - which is a bit unreasonable.]

If we reach the end of this keyspace without finding the it, we can then increase the range of permitted characters - WITHOUT undermining the work done.

[themandotcom]

I'm wondering, if we find the correct key, will it say "possible match" on the clients of something?

[poozle]

[cwmajors]

[David-A]

[cwmajors]

I seriously doubt there will be non-printables in the plaintext of the cypher - after all, MC -does- want this thing to be solved eventually. I just wanted to point out that the -key- does not necessarily have to be a printable-text key. In fact, if I were MC and I wanted to ensure that JoeBlow136 doesn't just -guess- the key, I'd make sure it completely random, without caring what the key is, because the key itself isn't important- the solve is.

As you said, there is an important distinction between the key and the solve that we need to remember. It would be very cute if the key was Violet's phone number or some such thing, but it would also destroy the point of the card, which is to crack a RC64 cypher.

My guess is that's exactly what we're being asked to do here. We will know very quickly when we've solved it, because we're using the same protocols that the distributed.net folks did.

At this rate, however, it's going to take us a while. My personal opinion is that it's going to take us plowing through the printables, then expanding outwards until we hit upon it.

[David-A]

[marky1124]

Whilst the key is limited to the 62 character key space don't forget that the decrypt text is being tested for printable ASCII characters which includes slashes etc that are used in ASCII art.

[fretty]

Was having a little read up about RC5 and was wondering. Looking at the site:

http://www.distributed.net/rc5/

Would it be right to assume that the message will start with

"the unknown message is:"

in the same style as the RSA challenges.

[Jones]

[jbd]

I should point out most plausable additions of punctuation increase the magnitude of the problem by years, not months.

Quoting chimera from the blog:

[Skizz]

I don't want to put a damper on things, but I've just noticed that the rccrypt program uses hex values for the key (unless I've misread it), i.e. the key is in the format "76fea2bc76a145e3" rather than "fivecows" which means the alphanumeric only key string is tenuous as you'd have to convert the string into a sequence of hex digits (not difficult) to use rccrypt. Anyone tried "beefbeefbeefbeef" as the keystring? (Admittedly it's only four cows!)

I have recently sent Chimera an update to that super fast cracking client I posted several pages back in this thread which should integrate with the existing code base quite easily - hopefully he'll have a chance soon to look at it. Now, if someone can get me an 64bit PC I could make it even faster....

Maybe we could do with a couple of these: http://www.reghardware.co.uk/2006/06/20/ibm_overclocking_feat/

Skizz

[cwmajors]