Create RSAcipher.go

Author: 0xbrayo

cachefile.dbm.dat

@@ -0,0 +1,172 @@
+package main
+
+import (
+	//"math/big"
+	"math/rand"
+	"math"
+	"time"
+	"fmt"
+)
+func generatePrimes(limit int)int{
+	/*
+	generate primes by factoring
+	relies on the 30k+i, though better formulae exist
+	where k >=0 and i = (1,7,11,13,17,13,19,23,29)
+	*/
+	primes:= prime(limit)
+	var choice []int
+	choice = append(choice, 1,7,11,13,17,19,23,29)
+	for{	
+		k:=rand.Intn(int(limit/30))
+		i:=choice[rand.Intn(len(choice))]
+		c:=30*k+i
+		found := true
+		for _,v:= range primes{
+			if c%v==0{
+				found = false
+				break
+			}
+		}
+		if found{
+			return c
+		}
+	}
+}
+func prime(limit int)(primes []int){
+	sqrtLimit:=int(math.Ceil(math.Sqrt(float64(limit))))
+	exit:= false
+	primes = append(primes,2,3,5)
+	lastIndex :=2
+	for ;primes[lastIndex]<sqrtLimit;{
+		if exit == true{
+			break
+		}
+		for i:=primes[lastIndex]+2;i<primes[lastIndex]*primes[lastIndex];i+=2{
+			found:= true
+			for _,v:= range primes {
+				if i%v==0{
+					found= false
+					break
+				}
+			}
+			if found{
+				primes = append(primes,i)
+				lastIndex++
+				if i >=sqrtLimit{
+					exit = true
+					break
+				}
+			}
+
+		}
+	}
+	return
+}
+func lcm (a int, b int)int{
+	//complexity depende
+	return int((a*b)/gcd(a,b))
+
+}
+func gcd (a int, b int) int{
+	//complexity not clear
+	for b != 0{
+		t:=b
+		b = a % b
+		a = t
+	}
+	return a
+}
+func modularMultiplicativeInverse(e int, delta int)int{
+	//runs in O(n) where n = delta
+	e= e % delta
+	for i:=1;i<delta;i++{
+		if (i*e)%delta==1{
+			return i
+		}
+	}
+	return 0
+}
+
+func modularExponentiation(b int, e int, mod int)int{
+	//runs in O(log(n)) where n = e
+	if mod == 1{
+		return 0
+	}
+	r:=1
+	b = b % mod
+	for ;e>0;{
+		if e%2==1{
+			r=(r*b)%mod
+		}
+		e =e>>1
+		b = (b*b)%mod
+	}
+	return r
+}
+
+func encryptRSA(message []int,e int,n int)[]int{
+	//runs in O(k*log(n)) where k = len(message) and n = e
+	var ciphertext []int
+	for _,v := range message{
+		ciphertext = append(ciphertext, modularExponentiation(v,e,n))
+	}
+	return ciphertext
+}
+func decryptRSA(ciphertext []int, d int, n int )[]int{
+	//runs in O(k*log(n)) where k = len(ciphertext) and n = d
+	var message []int
+	for _,v := range ciphertext {
+		message = append(message, modularExponentiation(v,d,n))
+	}
+	return message
+}
+func toASCII(slice []rune)[]int{
+	//runs in O(n) where n = len(slice)
+	var converted []int
+	for _,v:= range slice{
+		converted = append(converted, int(v))
+	}
+	return converted
+}
+
+func toRune(slice []int)string{
+	//runs in O(n) where n = len(slice)
+	var str string
+	for _,v:= range slice{
+		str += string(v)
+	}
+	return str
+}
+	
+
+func main(){
+	rand.Seed(time.Now().UTC().UnixNano())
+	bits:=15
+	
+	p:= generatePrimes(1<<bits)
+	q:= generatePrimes(1<<bits)
+	for p==q{
+		q = generatePrimes(1<<bits)
+	} 
+	
+	n:= p*q
+	
+	delta:=lcm(p-1,q-1)
+	
+	e:=generatePrimes(delta)
+	d:=modularMultiplicativeInverse(e,delta)
+
+	fmt.Printf("%v \n%v \n%v \n%v\n",p,q,e,d)
+	
+
+	str:="I think RSA is really great"
+	message := []rune(str)
+	asciiSlice :=toASCII(message)
+
+	fmt.Printf("asciiSlice :%v \n",asciiSlice)
+	encrypted := encryptRSA(asciiSlice,e,n)
+	fmt.Printf("encrypted :%v \n",encrypted)
+	decrypted := decryptRSA(encrypted,d,n)
+	fmt.Printf("decrypted : %v \n",decrypted)
+	fmt.Printf("cleartext : %v \n",toRune(decrypted))
+}

cachefile.dbm.dir

@@ -24,11 +24,18 @@ func decodeToString(slice []int)(str string){
 	}
 	return
 }
-
+func toASCII(slice []rune)[]int{
+	var converted []int
+	for _,v:= range slice{
+		converted = append(converted, int(v))
+	}
+	return converted
+}
 func main(){
-	//string = hello world
+	str := "hello world"
 	key :=97
-	message:=[]int{72,101,108,108,111,32,119,111,114,108,100}
+	temp:= []rune(str)
+	message:=toASCII(temp)
 	encrypted:=encrypt(key,message)
 	decrypted:=decrypt(key,encrypted)
 	plaintext:=decodeToString(decrypted)