Hot answers tagged dictionary-attack
10
Finding a decent explanation of rainbow tables was something I struggled with, so firstly I'll cover what they are. I will get to your question in the end. My sources for this are this guide and the wikipedia article.
Why can't I just use a big bucket of hashes?
Firstly the naive way to build a reverse lookup table is this. Let's say we want to generate ...
5
Rainbow tables are just a hyped-up name for tables of precomputed hash values with some trickery to allow for handling huuuuge tables in less huge storage space (e.g. mere terabytes).
Precomputed tables, including rainbow tables, are utterly defeated by salting. Assuming you used a proper password hashing process, one which includes a salt and can be ...
2
"Brute force" is a loosely-defined traditional expression to designate a kind of attack of low mathematical cleverness, namely trying all possible values for some unknown. For instance, in the context of symmetric encryption with AES, using a 128-bit key, "bruteforcing" would be trying all possible sequences of 128 bits as possible keys, until one matches ...
2
The security goal behind SRP is that an attacker that could either pretend to be a client (and attempt to log into a server that knows the key), pretend to be a server (and allow clients that know the key to attempt to log in), or actively monitor (and modify) the communications between a valid client and a valid server, would learn nothing from an exchange, ...
2
Rainbow tables can be used with words out of a dictionary rather than letters out of a charset.
The ophcrack vista liveCD is an example. In contains two dictionaries and tries combinations of words as well as modifications. For example the main dictionary contains "house" and "boat" and the second dictionary has "2010" "2011" "january". It will then ...
2
I believe that you are talking about one specific version of EKE, which is one of several known Password authenticated key agreement methods (which is the general category of methods that do a key agreement with the property that someone listening into the exchange can't learn anything, and an attacker that poses as one of the two sides can learn no more ...
1
Brute forcing the password, since no useful cryptanalysis of ICE is known.
I'm really more of a theory guy, so I don't know of any tools for this, but there are some resources that I've found.
http://security.stackexchange.com/questions/1376/where-can-i-find-good-dictionaries-for-dictionary-attacks answers its title's question, and ...
1
Based on the comments, it sounds like you know all the requirements/restrictions on the key. One thing that is not clear is if you have a good way of determining if a trial decryption resulted in the proper plaintext. This is usually not a difficult requirement as most data has some structure you could look for. Another important piece of information you are ...
1
As far as I know, NTLM v2 uses a MD5 HMAC with the user password as the key and the MD4 hash of the concenation of user name and domain.
MD5 itself isn't very secure as a hash (collisions are trivially to find), but it retains some value for applications like this one, since the best know preimage attack has about $2^{123}$ complexity (so almost the full ...
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