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So with rainbow tables, I think the speed of finding the password in a hash becomes more about I/O - how fast can the hash/password finder application dig through multi-terabyte files to match the hash you are looking for? In theory, if the rainbow tables are like indexed databases, even multi-terabyte files should yield a password recovery in a few seconds.
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Rainbow table are only useful when used against well known algorithms on unsalted hashes. (MD5)
For example WPA keys are generated with 4096 SHA1 iteration of the password + SSID as salt.
A specific rainbow table can be made for SSID "Linksys" but is completely useless against a "Router058" SSID.
Storing and indexing of rainbow tables is often much more costly than the generation and comparing process.