How does the SHA-512 decoder on the following page work? http://md5hashing.net/hashing/sha512#main

Hash values supposed to be unable to reverse. Is this page fake?

2 Answers 2


The site does only provide a rainbow table (a lookup of the possible text from the hash).

So it is simple a database with all hashes saved (so far because a user has entered the text for the searched hash before).

If you enter a hash value (e.g. 3d24c2171cac6da8435ff671c8408189688101be2581d20870a2cb508870048afec15eecd7ed8c406d4d86da746c8caf66db75d9060543dd5d29faca95819707) that was not hashed by them then the following error message appears:

Results not found in DB or your request exceed execution time. Anyways - please try again later.

Also they clearly state that they only provide a rainbow table:

"Decryption of hash (unsolted) is impossible, but we offer reverse decryption via our database (~245M records, and counting)."

  • 6
    Where do they state that they're using a rainbow table? The description it sounds like they don't: "in our DB we store millions (soon billions) of words and different strings aside to their hash". Also the number of 250M records is pretty low for a rainbow table. I'd assume that they use a simple lookup table, not a rainbow table. Apr 20, 2015 at 21:50
  • @CodesInChaos It depends on the concrete definition of rainbow table. They use a table of precomputed hashes to lookup the value for the hash. In my eyes this is a rainbow table. You never will have a rainbow table for all SHA512 hash values.
    – Uwe Plonus
    Apr 21, 2015 at 5:57
  • Rainbow tables use hash chaining to reduce the rate of growth below linear. Apr 21, 2015 at 6:00

Simple Answer: Rainbow Tables

This site save every Hashvalue you Entered to Hash it. So it could reverse search it in his own database.

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