/
main.go
194 lines (157 loc) · 5.34 KB
/
main.go
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package challenge8
import (
"cryptopals/set-1/challenge2"
//"encoding/base64"
"encoding/hex"
"fmt"
"log"
"os"
"strings"
"math/bits"
"bufio"
)
func main() {
// fmt.Println(CumputeDistance("this is a test", "wokka wokka!!!"))
file, err := os.Open("8.txt")
if err != nil {
log.Fatal(err)
}
defer file.Close()
//keysize:=16
scanner := bufio.NewScanner(file)
//var distances []float64
var iteration int
for scanner.Scan() {
//input := scanner.Text()
//tempBytes, _ := base64.StdEncoding.DecodeString(input)
//distances = append(distances, getNormalizedDistanceofKeysize(tempBytes, keysize, 5))
//fmt.Println(GetMinDistanceInKeysizeMultiComparison(tempBytes, keysize, 15), iteration)
iteration++
}
}
func GetNormalizedDistanceofKeysize(decodedBytesFromFile []byte, keysize int, nSlices int) float64 {
slices := make([][]uint8, nSlices) // initialize a slice of dy slices
for i:=0;i<nSlices;i++ {
slices[i] = decodedBytesFromFile[i*keysize : keysize*(i+1)]
}
distance := sumOfDistances(slices,16)
return float64(distance) / float64(keysize) / 12
}
func GetMinDistanceInKeysizeMultiComparison(decodedBytesFromFile []byte, keysize int, nSlices int) (minDistanceFound int, positionofDoubleByte int) {
slices := make([][]uint8, nSlices) // initialize a slice of dy slices
for i:=0;i<nSlices;i++ {
slices[i] = decodedBytesFromFile[i*keysize : keysize*(i+1)]
}
//fmt.Println(slices)
outsideValueForDoubleBytesPosition:=0
return MinOfDistances(slices,1000, 0, &outsideValueForDoubleBytesPosition), outsideValueForDoubleBytesPosition
}
func ComputeHammingDistance(str1 string, str2 string) (result int) {
bytes1 := []byte(str1)
bytes2 := []byte(str2)
for index, bits1 := range bytes1 {
bits2 := bytes2[index]
result += bits.OnesCount(uint(bits1) ^ uint(bits2))
}
return result
}
func sumOfDistances(slice [][]byte, currentSum int) (sum int) {
if len(slice) < 2 {return currentSum}
sliceTail := slice[1:len(slice)]
for _,e := range sliceTail {
currentSum += ComputeHammingDistance(hex.EncodeToString(slice[0]), hex.EncodeToString(e))
}
return sumOfDistances(sliceTail, currentSum)
}
func MinOfDistances(slice [][]byte, currentMin int, tempSliceNumber int, outsideValueForDoubleBytesPosition *int) (sum int) {
if len(slice) < 2 {return currentMin}
sliceTail := slice[1:len(slice)]
for _,e := range sliceTail {
temp := ComputeHammingDistance(hex.EncodeToString(slice[0]), hex.EncodeToString(e))
if currentMin > temp {
currentMin = temp
if temp==0 {
*outsideValueForDoubleBytesPosition = tempSliceNumber
fmt.Println("IM IN DOUBLE BYTE ASSIGNMENT")
}
}
}
tempSliceNumber++
return MinOfDistances(sliceTail, currentMin, tempSliceNumber, outsideValueForDoubleBytesPosition)
}
func sumOfDistances2(slices [][]byte) (distance int){
for i,slice1 := range slices {
for j,slice2 := range slices {
if (i>=j) {continue}
distance += ComputeHammingDistance(hex.EncodeToString(slice1), hex.EncodeToString(slice2))
}
}
return distance
}
func getMostProbableKeyLetter(input string) (int, string){
repeatedLetters := make([]string, 255)
decodedStrings := make([]string, 255)
for letter := 0; letter < 255; letter++ {
for i := 0; i < len(input)/len(hex.EncodeToString([]byte(string(letter)))); i++ {
repeatedLetters[letter] += hex.EncodeToString([]byte(string(letter)))
}
// fmt.Println("HERE")
// fmt.Println(len(repeatedLetters[letter]))
// fmt.Println(len(input))
// fmt.Println("HERE")
msg, err := challenge2.Fixed_XOR_on_hex_strings(input, repeatedLetters[letter])
if err != nil {
// fmt.Println(input, repeatedLetters[letter])
fmt.Println("PROBLEMS with XOR " + err.Error())
return 0,""
}
str2, err2 := hex.DecodeString(msg)
if err2 != nil {
fmt.Println("PROBLEMS with decoding the outcome hex")
// return 0,""
}
decodedStrings[letter] = string(str2)
}
return findMostEnglishString(decodedStrings)
}
func findMostEnglishString(decodedString []string) (letter int, bestString string) {
var maxCount int
for i , element := range decodedString {
currentCount := englishCount(element)
if currentCount > maxCount {
letter = i
bestString = element
maxCount = currentCount
}
}
return
}
func englishCount(input string) (count int) {
input = strings.ToLower(input)
for _ , element := range "etaoin shrdlu" {
count += strings.Count(input, string(element))
}
return
}
func CheckIfMinDistanceIsEqual3Times(decodedBytesFromFile []byte, keysize int) bool {
slices := make([][]uint8, len(decodedBytesFromFile)/keysize)
for i:=0;i<len(decodedBytesFromFile)/keysize;i++ {
slices[i] = decodedBytesFromFile[i*keysize : keysize*(i+1)]
}
return FindThreeEqualDistances(slices)
}
func FindThreeEqualDistances(slice [][]byte) (ThreeEqual bool) {
if len(slice) < 3 {return false}
sliceTail := slice[1:len(slice)]
ThreeEqual = false
FoundEqualDistanceOnce := false
for _,e := range sliceTail {
temp := ComputeHammingDistance(hex.EncodeToString(slice[0]), hex.EncodeToString(e))
if temp == 0 && FoundEqualDistanceOnce == true {
return true
} else if temp == 0 {
FoundEqualDistanceOnce = true
}
}
return FindThreeEqualDistances(sliceTail)
}