PoFSQ

PoFSQ: An Efficient File-Sharing Consensus Protocol

Proof of File-Sharing Qualification(PoFSQ). PoFSQ allows file-holders to verify with each other whether the shared-file has been preserved for a period of time. It also ensures that the content of shared-file is indeed what the file-downloader wants under the condition that more than 2/3 of participants are honest. Compared to the consensus protocol of Filecoin, PoFSQ is more efficient in the prover and verifier proof phases, because it uses a simple Proof of SpaceTime (PoST) of shared-file association to complete the qualification verification. Meanwhile, PoFSQ does not disclose the private information of shared-file during the consensus process, and does not rely on trusted third parties. This paper also implements and tests PoFSQ, and experimental results show that consensus can be reached efficiently.

Build the source:

go build main.go

./main.exe

Prover Initialization Phase

prover runs the parallel limited proof of work (PL-PoW) to generate the evidence file. Difficulty value can be adjusted dynamically and it determines the difficulty of PL-PoW. In this project, readbitlen is the difficulty value, as follows:

const (
	readbitlen int64 = 10
)

The evidence file includes two parts: node file ending in .block and random number file ending in .nonce. For example, Initialize the "1K" file will generate "1K.block" and "1K.nonce" files.

Prover Proof Phase

Any verifier can challenge the prover by sending a random string ch. Upon receiving the challenge, prover utilizes the preserved evidence file to generate response message.

In this project, the value of ch is fixed, as follows:

var ch string = "12345678901234567890123456789014"

This phase will generate the response results, as follows:

node := proverProofPhase.GenerateMerkleTree(filename,readbitlen,identity,ch)

node is the response result which includes the selected node and the path from the corresponding node to the root node.

Verifier Proof phase

When verifiers receive the response result, they begin to verify:

verifierProofPhase.Verify(node,filename,identity,readbitlen,ch)

Example of program running:

Contract:

sushuai@iie.ac.cn

yuanfangyuan@iie.ac.cn