Initial commit, after some cleanup

Author: robquant

challenge1_1.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"log"
+)
+
+//import "encoding/hex"
+
+const (
+	input        = "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d"
+	expected     = "SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t"
+	inputWiki    = "Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure."
+	expectedWiki = "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlzIHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2YgdGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGludWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRoZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVhc3VyZS4="
+	encodeStd    = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+)
+
+func base64(c byte) byte {
+	return encodeStd[c]
+}
+
+func encode(input []byte) []byte {
+	decoded := input
+	// Pad with 0 bytes
+	for len(decoded)%3 != 0 {
+		decoded = append(decoded, 0)
+	}
+
+	var result []byte
+	for i := 0; i < len(decoded)/3; i++ {
+		current := uint32(decoded[3*i]) << 16
+		current |= uint32(decoded[3*i+1]) << 8
+		current |= uint32(decoded[3*i+2])
+		for b := 3; b >= 0; b-- {
+			shiftBy := 6 * b
+			mask := uint32(63) << shiftBy
+			r := byte((current & mask) >> shiftBy)
+			result = append(result, base64(r))
+		}
+	}
+	fillBytes := len(decoded) - len(input)
+	for i := 0; i < fillBytes; i++ {
+		result[len(result)-1-i] = '='
+	}
+	return result
+}
+
+func main() {
+	decoded, _ := hex.DecodeString(input)
+	result := encode(decoded)
+	resultWikipedia := encode([]byte(inputWiki))
+	if string(resultWikipedia) != expectedWiki {
+		log.Fatal("Not equal wikipedia!")
+	} else {
+		fmt.Println("Yeah!")
+	}
+	if string(result) != expected {
+		log.Fatal("Not equal!")
+	} else {
+		fmt.Println("Yeah!", string(decoded))
+	}
+}

challenge1_2.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"log"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+const (
+	inputS    = "1c0111001f010100061a024b53535009181c"
+	keyS      = "686974207468652062756c6c277320657965"
+	expectedS = "746865206b696420646f6e277420706c6179"
+)
+
+func main() {
+
+	input, _ := hex.DecodeString(inputS)
+	key, _ := hex.DecodeString(keyS)
+	xored, err := tools.Xor(input, key)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if expectedS != hex.EncodeToString(xored) {
+		fmt.Printf("Expected: %s\nGot     : %s\n", expectedS, hex.EncodeToString(xored))
+		log.Fatal("Not equal!")
+	} else {
+		expected, _ := hex.DecodeString(expectedS)
+		fmt.Println("Yeah!", string(expected))
+	}
+}

challenge1_3.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strings"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+const (
+	secretS = "1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736"
+)
+
+func main() {
+
+	secretRaw, _ := hex.DecodeString(secretS)
+	secret := []byte(strings.ToLower(string(secretRaw)))
+	bestKey, _ := tools.GuessKey(secret)
+	decrypted := tools.XorSingleLetter(secret, bestKey)
+	decryptedS := strings.ToLower(string(decrypted))
+	fmt.Printf("Key: %c -> Decrypted: %v\n", rune(bestKey), decryptedS)
+
+}

challenge1_4.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+func main() {
+
+	f, _ := os.Open("input/input1_4.txt")
+	scanner := bufio.NewScanner(f)
+	overallBestScore := 999.0
+	var decryptedText string
+	for scanner.Scan() {
+		secretRaw, _ := hex.DecodeString(scanner.Text())
+		secret := []byte(strings.ToLower(string(secretRaw)))
+		bestKey, bestScore := tools.GuessKey(secret)
+		decrypted := tools.XorSingleLetter(secret, bestKey)
+		decryptedS := string(decrypted)
+		if bestScore < overallBestScore {
+			overallBestScore = bestScore
+			decryptedText = decryptedS
+		}
+	}
+	fmt.Printf("Score: %.3f -> Decrypted: %v\n", overallBestScore, decryptedText)
+
+}

challenge1_6.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"log"
+
+	"encoding/base64"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+func main() {
+	b1 := []byte("this is a test")
+	b2 := []byte("wokka wokka!!!")
+	fmt.Printf("Hamming distance: %d\n", tools.HammingDistance(b1, b2))
+	input, _ := ioutil.ReadFile("input/input1_6.txt")
+	lines := bytes.Split(input, []byte("\n"))
+	joined := bytes.Join(lines, []byte(""))
+	decoded, err := base64.StdEncoding.DecodeString(string(joined))
+	if err != nil {
+		log.Fatal("Decoding error ", err)
+	}
+	keyLength := tools.GuessKeyLength(decoded)
+	transposed := tools.Transpose(decoded, keyLength)
+	key := make([]byte, keyLength)
+	for i := 0; i < keyLength; i++ {
+		keyLetter, _ := tools.GuessKey(transposed[i])
+		key[i] = keyLetter
+	}
+	fmt.Printf("Key: %s", string(key))
+	fmt.Printf("%s", string(tools.RepeatedKeyXor(decoded, key)))
+}

challenge1_7.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"strings"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+func main() {
+	key := []byte("YELLOW SUBMARINE")
+
+	inputBytes, err := ioutil.ReadFile("input/input1_7.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	input := strings.Replace(string(inputBytes), "\n", "", 0)
+	ciphertext, _ := base64.StdEncoding.DecodeString(input)
+	plaintext := tools.DecryptAesECB(ciphertext, key)
+	fmt.Printf("%s\n", string(plaintext))
+}

challenge1_8.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+func main() {
+	inputBytes, _ := ioutil.ReadFile("input/input1_8.txt")
+	lines := bytes.Split(inputBytes, []byte("\n"))
+	for i, line := range lines {
+		if repeatedBlocks := tools.CountSameBlocks(line, 16); repeatedBlocks > 0 {
+			fmt.Printf("Line %d has %d repetitions\n", i+1, repeatedBlocks)
+		}
+	}
+}

challenge2_1.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/robquant/cryptopals/pkg/tools"
+)
+
+func main() {
+	fmt.Printf("%v\n", tools.Pkcs7Pad([]byte("YELLOW SUBMARINE"), 20))
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/robquant/cryptopals
+
+go 1.13