[cynwoody]

The “an essay” has 7 such facilities, the one in Utah everyone talks about, and six more scattered across the land.

The number I've heard bandied about is yottabyte. A yottabyte is 1e24 bytes. The output of the SHA1 function is 20 bytes long.

If you allow all the printable ASCII (95 characters) in passwords, the number of 13-character passwords is 95**13, or 51334208327950511474609375. To store that many 20-byte hashes, you'd need over a thousand yottabytes. But, barring a major break-through in storage technology, I think it's be quite a while before Bluffedale holds even one full yottabyte.

Recently Brewster Kahle (the guy behind the Wayback Machine) estimated the cost of storing a year's worth of US phone audio at about $29m. The amount of storage needed? 272 petabytes. There are a billion petabytes in a yottabyte.

[null and void]

If I understand what you are saying, in order to get every possible input that would result in any 20 byte hash, you would need 1e27 bytes.

The question is how many inputs would you need to store to generate all possible 20 byte hashes?

That is a far smaller number.

If I have a unique 20 byte hash, to get into the account I only need ONE of the 2x10⁶ or so possible combinations that generates that particular 20 byte hash, I don't need ALL of them.