lbry.com/content/faq/proof-algorithm.md

title	category
What is LBRY's proof algorithm?	mining

What is LBRY's proof algorithm?

LBRY uses proof of work the same way that Bitcoin does. The only difference is the hash function. LBRY uses a sligthly 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 algorimth is

intermediate = sha512(sha256(sha256(data)))  # compute the sha512() of the double-sha256() of the data
left = ripemd(x[:len(x)/2])  # separately ripemd160 the left half
right = ripemd(x[len(x)/2:]) # and the right half
proof = sha256(sha256(left + right))  # concatenate the two halves, and double-sha256() it again

For comparison, Bitcoin's algorimth is

proof = sha256(sha256(data))