Devil Traumae nick generator, based on @pedrox's exploit

devil.go

// http://events.ccc.de/congress/2011/Fahrplan/attachments/2007_28C3_Effective_DoS_on_web_application_platforms.pdf
// Original by pedrox (https://gist.github.com/pedrox/eb8d674bf2b8be63da0f)

package main

import (
    "fmt"
    "math/rand"
    "strconv"
)

func rev(h int, prefix []byte) int {
    for i := len(prefix) - 1; i >= 0; i-- {
        h = ((h - int(prefix[i])) * 3186588639) & 0xffffffff
    }
    return h
}

func fwd(h int, prefix []byte) int {
    for i := 0; i < len(prefix); i++ {
        h = ((h * 31) + int(prefix[i])) & 0xffffffff
    }
    return h
}

func voworcons(b int) byte {
    var allowed []byte
    if b == 0 {
        allowed = []byte("ktpxdbslv")
    } else {
        allowed = []byte("iao")
    }
    return allowed[rand.Intn(len(allowed))]
}

func rndstr(l int) []byte {
    out := make([]byte, l)
    for i := 0; i < l; i++ {
        out[i] = voworcons(i % 2)
    }
    return out
}

func precompute(ttotal, arg int, val chan map[int][]byte) {
    suffix_lookup := make(map[int][]byte)
    col := 0
    strthread := strconv.Itoa(ttotal - arg)
    for i := 0; i < 1048576; i++ {
        prefix := rndstr(6 + arg)
        h := rev(666, prefix)
        if _, ok := suffix_lookup[h]; ok {
            col += 1
        } else {
            suffix_lookup[h] = prefix
        }
    }
    fmt.Println("#" + strthread + " " + "collisions: " + strconv.Itoa(col))
    val <- suffix_lookup
}

func findCollisions(arg int, suffix_lookup map[int][]byte, end chan bool) {
    found := 0
    iteration := 0
    foundItems := make(map[int]bool)
    for {
        prefix := rndstr(2 + arg)
        h := fwd(0, prefix)
        if _, ok := foundItems[h]; !ok {
            if _, ok2 := suffix_lookup[h]; ok2 {
                if (len(prefix)+len(suffix_lookup[h]))%2 != 0 {
                    fmt.Printf(string(prefix) + string(suffix_lookup[h]) + "\r\n")
                }
                found += 1
                foundItems[h] = true
            }
        }
        iteration += 1
    }
}

func main() {
    suffix_lookup := make(map[int][]byte)
    rand.Seed(42)
    ttotal := 8
    fmt.Println("precomputing " + strconv.Itoa(ttotal) + "M hashes on " + strconv.Itoa(ttotal) + " threads...")
    chans := make([]chan map[int][]byte, ttotal)
    for i := 0; i < ttotal; i++ {
        chans[i] = make(chan map[int][]byte)
        go precompute(ttotal, i, chans[i])
    }
    for i := 0; i < ttotal; i++ {
        mapv := <-chans[i]
        for k, v := range mapv {
            suffix_lookup[k] = v
        }
    }
    fmt.Println("Starting " + strconv.Itoa(ttotal) + " MITM threads")
    ends := make([]chan bool, ttotal)
    for i := 0; i < ttotal; i++ {
        ends[i] = make(chan bool)
        go findCollisions(i, suffix_lookup, ends[i])
    }
    for i := 0; i < ttotal; i++ {
		<-ends[i]
	}
}

Nice!