Program to find crc32 collision

main.go

package main

import (
	"fmt"
	"hash/crc32"
	"io/ioutil"
	"log"
	"runtime"
	"strings"
	"sync"
)

var routines uint32 = 8

func main() {
	runtime.GOMAXPROCS(int(routines))

	var wg sync.WaitGroup

	var i uint32
	for i = 0; i < routines; i = i + 1 {
		wg.Add(1)
		go func(buc uint32) {
			dataFile, err := ioutil.ReadFile("quine-crc.js")
			if err != nil {
				log.Fatal(err)
			}
			baseTemplateString := string(dataFile[:])
			parts := strings.Split(baseTemplateString, "{{Pad}}")
			var pad uint32 = 681180860
			for {
				pad += 1
				if pad == 0 {
					wg.Done()
					break
				}
				if pad%routines != buc {
					continue
				}
				curQuine := strings.Join(parts, fmt.Sprintf("0x%08x", pad))
				cksum := crc32.ChecksumIEEE([]byte(curQuine))
				if cksum == pad {
					log.Printf("Found it dec: %d hex: 0x%08x", pad, pad)
					log.Println(cksum)
					log.Printf("%s", curQuine)
					log.Fatal("done")
					break
				}
				if pad%1000000 == 0 {
					log.Printf("%d", pad)
					log.Printf("%s", curQuine)
				}
			}
		}(i)
	}
	wg.Wait()
	log.Println("Finished without finding collision")

}

@praetoriansentry Can I ask, why do you start the pad with 681180860? It seems like a pretty random number, why would 0 be worse? Thank you!

I'm not sure. I'm just guessing, but probably what I did was hard code the first collision that I found so that I could re-run it quickly for verification purposes. I would guess a 0 is fine.