2019-02-15 11:50:56 -05:00
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---
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title: Consensus Algorithm
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description: How does the LBRY blockchain achieve consensus? This resource page will explain.
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---
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2018-07-13 13:03:21 -05:00
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2019-02-19 13:11:46 -05:00
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LBRY uses [proof of work](https://en.bitcoin.it/wiki/Proof_of_work) as a [consensus mechanism](/spec#consensus), the same way that Bitcoin does.
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2018-07-13 13:03:21 -05:00
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2020-05-01 10:09:21 -07:00
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LBRY has differences in hash function, block targeting, and difficulty adjustment.
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2018-09-30 13:34:29 -04:00
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### Hash Mechanism
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2018-07-13 13:03:21 -05:00
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```python
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intermediate = sha512(sha256(sha256(data))) # compute the sha512() of the double-sha256() of the data
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left = ripemd(intermediate[:len(intermediate)/2]) # separately ripemd160 the left half
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right = ripemd(intermediate[len(intermediate)/2:]) # and the right half
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proof = sha256(sha256(left + right)) # concatenate the two halves, and double-sha256() it again
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```
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2019-01-12 11:34:10 -08:00
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### Block Targeting & Difficulty Adjustment
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2018-07-13 13:03:21 -05:00
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2020-05-01 10:09:21 -07:00
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The targeted time of each LBRY block is 2.5 mintues (150 seconds). More information and links to source code [here](https://lbry.tech/spec#consensus).
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