arno/bitcoinbook
1
0
Fork 0
mirror of https://github.com/bitcoinbook/bitcoinbook synced 2024-12-27 00:48:09 +00:00
Code Issues Releases Wiki Activity

Edited ch10.asciidoc with Atlas code editor

Browse Source
This commit is contained in:
judymcconville@roadrunner.com 2017-05-02 11:14:17 -07:00
parent a15f332ec5
commit ce544cd873
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
ch10.asciidoc
View File

@ -416,7 +416,7 @@ With all the other fields filled, the block header is now complete and the proce
==== Proof-of-Work Algorithm
((("mining and consensus", "mining the block", "Proof-of-Work algorithm")))((("Proof-of-Work algorithm", id="proof10")))((("consensus", "Proof-of-Work algorithm", id="Cproof10")))A hash algorithm takes an arbitrary-length data input and produces a fixed-length deterministic result, a digital fingerprint of the input. For any specific input, the resulting hash will always be the same and can be easily calculated and verified by anyone implementing the same hash algorithm. The key characteristic of a cryptographic hash algorithm is that it is computationally infeasible to find two different inputs that produce the same fingerprint (known as a _collision_). As a corollary, it is also virtually impossible to select an input in such a way as to produce a desired fingerprint, other than trying random inputs.
((("mining and consensus", "mining the block", "Proof-of-Work algorithm")))((("Proof-of-Work algorithm", id="proof10")))((("consensus", "Proof-of-Work algorithm", id="Cproof10")))A hash algorithm takes an arbitrary-length data input and produces a fixed-length deterministic result, a digital fingerprint of the input. For any specific input, the resulting hash will always be the same and can be easily calculated and verified by anyone implementing the same hash algorithm. ((("collisions")))The key characteristic of a cryptographic hash algorithm is that it is computationally infeasible to find two different inputs that produce the same fingerprint (known as a _collision_). As a corollary, it is also virtually impossible to select an input in such a way as to produce a desired fingerprint, other than trying random inputs.
With SHA256, the output is always 256 bits long, regardless of the size of the input. In <<sha256_example1>>, we will use the Python interpreter to calculate the SHA256 hash of the phrase, "I am Satoshi Nakamoto."