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August 01, 2012, 10:16:16 PM |
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Keep in mind I'm wet behind the ears cryptographically speaking. So I was thinking today....very soon I'm going to be setting up a brain wallet. I will use the SHA256 hash of a passphrase....probably words pulled at "random" from a dictionary (correct horse battery staple).
It occurred to me that to make it extra secure against brute force attacks, I could get the hash of all those words except 1 of them, then append that one word to the SHA256 hash of the others. Is this a good idea? Is this what people talk about when they refer to a "salt?"
Example:
SHA256 (Barack Obama) = d8f758500c5d3303786d5638bb720775769f52064dfb669d3540ac9074acf30e
But that would get busted wide open by a dictionary attack in short order, I'm guessing.
So let's do.... SHA256 (Barack) = 891bd7ecb4ef7e1a70bec2585132036929dd0d1262674a44ec531a916715e7f4
and then...
SHA256 (Obama891bd7ecb4ef7e1a70bec2585132036929dd0d1262674a44ec531a916715e7f4) = a0bb198d05696ba0addfea88489e75d42ef8b5bf7bfcdf68df9dccb70f231832
So my for my private key I would use a0bb198...1832
Is this a good idea?
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