LBRY uses [proof of work](https://en.bitcoin.it/wiki/Proof_of_work) the same way that Bitcoin does. The
only difference is the hash function. LBRY uses a slightly different algorithm that achieves the same ends but slightly delayed the development of a GPU miner and gave early adopters a chance to mine without specialized hardware.
LBRY's algorithm is
```python
intermediate = sha512(sha256(sha256(data))) # compute the sha512() of the double-sha256() of the data
left = ripemd(intermediate[:len(intermediate)/2]) # separately ripemd160 the left half
right = ripemd(intermediate[len(intermediate)/2:]) # and the right half
proof = sha256(sha256(left + right)) # concatenate the two halves, and double-sha256() it again