Mining Bitcoin with pencil and paper: 0.67 hashes per day (2014)

Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by bogomipz on Monday December 18, 2017 @10:35AM (#15952277)

>"Currently, a successful hash must start with approximately 17 zeros, so only one out of 1.4 x 10^20 hashes will be successful."

Can someone elaborate on the math here? How do we get to 1 in 1.4 x 10^20 ?

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Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by carry_bit on Monday December 18, 2017 @11:17AM (#15952664)

It's probably 17 hexadecimal zeros.

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Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by dmurray on Monday December 18, 2017 @09:34PM (#15957296)

Yes, as shown in the second image in the article where the successful hash starts with sixteen hexadecimal zeros.

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Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by bogomipz on Tuesday December 19, 2017 @12:43AM (#15958057)

I'm still not following can you break it down?

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Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by dmurray on Tuesday December 19, 2017 @07:13PM (#15965814)

The hash is a cryptographically random number. For it to be successful, it must start with seventeen zeros (base 16). The chance of a random number starting like that is 1 in 16^17, which is about equal to 1 in 3 x 10^20.

I can't reproduce the calculation from the article that got 1.4 x 10^20. But it does say "approximately 17 zeros" so maybe it really meant "the first 16 hex digits must be zero and the 17th must be either zero or one". That would give close to the right numbers, if I haven't messed up.

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Re:Mining Bitcoin with pencil and paper: 0.67 hashes per day... by nerdlogic on Monday December 18, 2017 @11:01AM (#15952517)

Assuming uniformly random hashes, shouldn't it be 1/2^17?

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