RainbowCrack is a computer program which generates rainbow tables to be used in password cracking

Password cracking

Password cracking is the process of recovering passwords from data that has been stored in or transmitted by a computer system. A common approach is to repeatedly try guesses for the password...

. RainbowCrack differs from "conventional" brute force crackers in that it uses large pre-computed tables called rainbow table

Rainbow table

A rainbow table is a precomputed table for reversing cryptographic hash functions, usually for cracking password hashes. Tables are usually used in recovering the plaintext password, up to a certain length consisting of a limited set of characters. It is a form of time-memory tradeoff, using less...

s to reduce the length of time needed to crack a password drastically. RainbowCrack was developed by Zhu Shuanglei, and implements an improved time-memory trade-off cryptanalysis

Cryptanalysis

Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information that is normally required to do so. Typically, this involves knowing how the system works and finding a secret key...

 attack which originated in Philippe Oechslin's Ophcrack

Ophcrack

Ophcrack is a free open source program that cracks Windows passwords by using LM hashes through rainbow tables. The program includes the ability to import the hashes from a variety of formats, including dumping directly from the SAM files of Windows...

.

As RainbowCrack's purpose is to generate rainbow tables and not to crack passwords per-se, some organizations have endeavored to make RainbowCrack's rainbow tables available free over the internet.

External links

• Project RainbowCrack - Developer's official site.
• Rainbow Tables & Rainbow Crack tutorial