brute force hash (md5, sha1) first char in Go using combinaison from Python or rand

brutus-combinaison.go

package main

import (
    "fmt"
    "os"
    "crypto/md5"
    //"crypto/sha1"
    //"math/rand"
    "time"
    "encoding/hex"
    "strings"
    "strconv"
    "bytes"
)

var start = time.Now()

var prefix = os.Args[1]
var length = os.Args[2]

func combinations(iterable []int, r int) {
    pool := iterable
    n := len(pool)

    if r > n {
        return
    }

    indices := make([]int, r)
    for i := range indices {
        indices[i] = i
    }

    result := make([]int, r)
    for i, el := range indices {
        result[i] = pool[el]
    }

    //fmt.Println(result)

    for {
        i := r - 1
        for ; i >= 0 && indices[i] == i+n-r; i -= 1 {
        }

        if i < 0 {
            return
        }

        indices[i] += 1
        for j := i + 1; j < r; j += 1 {
            indices[j] = indices[j-1] + 1
        }

        for ; i < len(indices); i += 1 {
            result[i] = pool[indices[i]]
        }

        var buffer bytes.Buffer
        for i := 0; i < len(result); i++ {
            fmt.Printf("combinations %s\n",attemp)
            buffer.WriteString(string(result[i]))
        }
        res := pown(buffer.String())
        if res {
            break
        }
    }

}

func pown(attemp string) bool {
    hash := md5.New()
        hash.Write([]byte(attemp))                
        hashString := hex.EncodeToString(hash.Sum(nil))

    //compare the cmdline input with the md5 prefix 
    if strings.HasPrefix(hashString,prefix){
        fmt.Printf("combinations %s\n",attemp)
        return true
    }
    return false
}

func main() {
    // add some randomness
    //rand.Seed(time.Now().UnixNano())

    l, err := strconv.Atoi(length)
    if err != nil {
        // handle error
        fmt.Println(err)
        os.Exit(2)
    }

    var charset = []int{97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 
        107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 
        120, 121, 122, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 
        78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 48, 49, 50, 51, 
        52, 53, 54, 55, 56, 57, 61, 47, 43}

    combinations(charset, l)

    elapsed := time.Since(start)
    fmt.Println(elapsed)
}

brutus-rand.go

package main

import (
    "fmt"
    "os"
    "crypto/md5"
    //"crypto/sha1"
    "math/rand"
    "time"
    "encoding/hex"
    "strings"
    "strconv"
)

var start = time.Now()

var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789=/+")
//var letters = []rune("!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|")

func randSeq(n int) string {
    b := make([]rune, n)
    for i := range b {
        b[i] = letters[rand.Intn(len(letters))]
    }
    return string(b)
}

func pown(nonce string, n int) {
    //generate md5 from random strings
    for {
        attemp := randSeq(n)
        //hash := sha1.New()
        hash := md5.New()
            hash.Write([]byte(attemp))    
            hashString := hex.EncodeToString(hash.Sum(nil))

        //compare the cmdline input with the md5 nonce 
        if strings.HasPrefix(hashString,nonce){
            fmt.Printf("random %s\n",attemp)
            break
        }
        
    }
}

func main() {
    // ad some randomness
    rand.Seed(time.Now().UnixNano())

    //argument from cmdline
    prefix := os.Args[1]
    length := os.Args[2]
    n, err := strconv.Atoi(length); 
    if err != nil { 
      // Invalid string 
    }

    pown(prefix,n)

    elapsed := time.Since(start)
    fmt.Println(elapsed)
}