Decode sha256 hash with number less than or equal 100000000

sha256_decode.go

package main

import (
	"bufio"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
	"time"
)

func contains(s []string, e string) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func createAndMatch(hashList []string, s string) (string, bool) {
	h := sha256.New()
	h.Write([]byte(s))
	sha_hash := hex.EncodeToString(h.Sum(nil))
	return sha_hash, contains(hashList, sha_hash)
}

func process(hashList []string) {
	count := len(hashList)
	for i := 99999999; i > 0; i-- {
		if count == 0 {
			return
		}
		s := strconv.Itoa(i)
		hash, match := createAndMatch(hashList, s)
		if match {
			fmt.Println(hash, "\t", s)
			count--
		}
		// if i%100000 == 0 || i == 1 {
		// 	fmt.Println(s)
		// }
	}
}

func readFile(filePath string) []string {
	file, err := os.Open(filePath)
	if err != nil {
		panic("failed to open")
	}
	scanner := bufio.NewScanner(file)
	scanner.Split(bufio.ScanLines)
	var text []string
	for scanner.Scan() {
		text = append(text, strings.TrimSpace(scanner.Text()))
	}
	file.Close()
	return text
}

func getHashList(args []string) []string {
	if len(args[0]) != 64 {
		return readFile(args[0])
	}
	return args
}

func elapsed(what string) func() {
	start := time.Now()
	return func() {
		fmt.Printf("%s took %v\n", what, time.Since(start))
	}
}

func main() {
	args := os.Args[1:]
	if len(args) == 0 {
		log.Fatalf("No argument. Are you kidding!")
		return
	}
	hashList := getHashList(args)
	fmt.Println("Number of hash: ", len(hashList))
	fmt.Printf("Finding for %v\n", hashList)
	fmt.Println("..............")
	fmt.Println("....................")
	defer elapsed("Find process")()
	process(hashList)
	fmt.Println("------------------------------------------------------------------------------------------------")
}

sha256_generate.go

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"strconv"
)

func contains(s []string, e string) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func createAndMatch(s string) {
	h := sha256.New()
	h.Write([]byte(s))
	sha_hash := hex.EncodeToString(h.Sum(nil))
	fmt.Println(sha_hash + "," + s)
}

func process() {
	for i := 99999999; i > 0; i-- {
		s := strconv.Itoa(i)
		createAndMatch(s)
	}
}

func main() {
	process()
}