Go md5-bruteforce (par.)

package main

import (
    "crypto/md5"
    "encoding/hex"
    "fmt"
    "log"
    "runtime"
    "time"
)

var hash [16]byte

func nextByte(b byte) byte {
    switch b {
    case 'z':
        return '0'
    case '9':
        return 'a'
    default:
        return b + 1
    }
}

func nextPass(b []byte) {
    for i := len(b) - 1; i >= 0; i-- {
        b[i] = nextByte(b[i])
        if b[i] != '0' {
            return
        }
    }
}

type part struct {
    start string
    end   byte
}

// worker по порядку сравнивает хэш каждого пароля с искомым
func worker(in <-chan part, out chan<- string) {
    var p part
    var b []byte
    for {
        p = <-in
        b = []byte(p.start)
        for b[0] != p.end {
            if md5.Sum(b) == hash {
                out <- string(b)
                return
            }
            nextPass(b)
        }
    }
}

func generator(in chan<- part) {
        start := []byte("00000")
        var b byte
        for {
            b = nextByte(start[0])
            in <- part{string(start), b}
            start[0] = b
        }
}

func main() {
    t := time.Now()
    const hashString = "95ebc3c7b3b9f1d2c40fec14415d3cb8" // "zzzzz"
    h, err := hex.DecodeString(hashString)
    if err != nil {
        log.Fatal(err)
    }
    copy(hash[:], h)
    num := runtime.NumCPU()
    runtime.GOMAXPROCS(num)
    in := make(chan part)
    out := make(chan string)
    go generator(in)
    for i := 0; i < num; i++ {
        go worker(in, out)
    }
    fmt.Println("Пароль: ", <-out)
    fmt.Println("Время поиска: ", time.Since(t))
}