From ebb10109c9dfd688699aa8c88dd22e8fcbf6870f Mon Sep 17 00:00:00 2001 From: "myarbrough@oreilly.com" Date: Tue, 18 Nov 2014 11:25:03 -0800 Subject: [PATCH] Made changes to ch08.asciidoc --- ch08.asciidoc | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/ch08.asciidoc b/ch08.asciidoc index 2a6597fc..9e67dc4c 100644 --- a/ch08.asciidoc +++ b/ch08.asciidoc @@ -569,9 +569,9 @@ Hashing Power: 127141 hashes per second ---- ==== -As you can see, increasing the difficulty by 1 bit causes an exponential increase in the time it takes to find a solution. If you think of the entire 256-bit number space, each time you constrain one more bit to zero, you decrease the search space by half. In <>, it takes 84 million hash attempts to find a nonce that produces a hash with 26 leading bits as zero. Even at a speed of more than 120 thousand hashes per second, it still requires 10 minutes on a consumer laptop to find this solution. +As you can see, increasing the difficulty by 1 bit causes an exponential increase in the time it takes to find a solution. If you think of the entire 256-bit number space, each time you constrain one more bit to zero, you decrease the search space by half. In <>, it takes 84 million hash attempts to find a nonce that produces a hash with 26 leading bits as zero. Even at a speed of more than 120,000 hashes per second, it still requires 10 minutes on a consumer laptop to find this solution. -At the time of writing this, the network is attempting to find a block whose header hash is less than +000000000000004c296e6376db3a241271f43fd3f5de7ba18986e517a243baa7+. As you can see, there are a lot of zeros at the beginning of that hash, meaning that the acceptable range of hashes is much smaller, hence more difficult to find a valid hash. It will take on average more than 150 quadrillion hash calculations per second for the network to discover the next block. That seems like an impossible task, but fortunately the network is bringing 100 petahashes per second (PH/sec) of processing power to bear, which will be able to find a block in about 10 minutes on average.(((range="endofrange", startref="ix_ch08-asciidoc16")))(((range="endofrange", startref="ix_ch08-asciidoc15"))) +At the time of writing, the network is attempting to find a block whose header hash is less than +000000000000004c296e6376db3a241271f43fd3f5de7ba18986e517a243baa7+. As you can see, there are a lot of zeros at the beginning of that hash, meaning that the acceptable range of hashes is much smaller, hence more difficult to find a valid hash. It will take on average more than 150 quadrillion hash calculations per second for the network to discover the next block. That seems like an impossible task, but fortunately the network is bringing 100 petahashes per second (PH/sec) of processing power to bear, which will be able to find a block in about 10 minutes on average.(((range="endofrange", startref="ix_ch08-asciidoc16")))(((range="endofrange", startref="ix_ch08-asciidoc15"))) [[difficulty_bits]] ==== Difficulty Representation