go-por

A Golang implementation of publicly-verifiable proofs of retrievability, based on work by Shacham and Waters.

Theory

The theory behind the proofs is detailed in Compact Proofs of Retrievability, by Hovav Shacham and Brent Waters. In particular, it implements the Construction with RSA Signatures detailed in section 6.

Implementation

The current implementation tags the file example.txt with an RSA 2048-bit keypair (λ_1 - 1 = 2048), issues a verification request with l = 2 elements, and checks for its correctness.

Example usage

package main;

import (
	"fmt"
	"github.com/CapacitorSet/por"
	"os"
)

func main() {
	fmt.Printf("Generating RSA keys...\n")
	spk, ssk := Keygen()
	fmt.Printf("Generated!\n")

	fmt.Printf("Signing file...\n")
	file, err := os.Open("./example.txt")
	if err != nil {
		panic(err)
	}
	tau, authenticators := St(ssk, file)
	fmt.Printf("Signed!\n")

	fmt.Printf("Generating challenge...\n")
	q := Verify_one(tau, spk)
	fmt.Printf("Generated!\n")

	fmt.Printf("Issuing proof...\n")
	mu, sigma := Prove(q, authenticators, spk, file)
	fmt.Printf("Issued!\n")

	fmt.Printf("Verifying proof...\n")
	yes := Verify_two(tau, q, mu, sigma, spk)
	fmt.Printf("Result: %t!\n", yes)
	if yes {
		os.Exit(0)
	} else {
		os.Exit(1)
	}
}