Envisiontec Ultra 3DP SLA printer/encrypt

C++ version by RSpliet :

#include <string>
#include <iostream>

using namespace std;
class crypt {
private:
void SwapCharacter(string &csString, int iPosA, int iPosB)
{
	char ch1 = csString[iPosA];
	char ch2 = csString[iPosB];
	csString[iPosA] = ch2;
	csString[iPosB] = ch1;
}

int GetNextReturn(int iInitialIndex)
{
	int num;
	do
	{
		++iInitialIndex;
		num = 2;
		while (num < iInitialIndex && iInitialIndex % num != 0)
			++num;
	} while (num != iInitialIndex);
	return iInitialIndex;
}

int GetPrimaryIndex(int iIndex)
{
	int iInitialIndex = 1;
	for (int index = 1; index < iIndex; ++index)
		iInitialIndex = GetNextReturn(iInitialIndex);
	return iInitialIndex;
}

public:
string Decrypt(string csString)
{
	for (int index = csString.length() - 1; index >= 0; --index) {
		int iPosB = index;
		int iPosA = GetPrimaryIndex(index + 3) % csString.length();
		SwapCharacter(csString, iPosA, iPosB);
	}
	return csString;
}

string Encrypt(string csString)
{
	for (int index = 0; index < csString.length(); index++) {
		int iPosB = index;
		int iPosA = GetPrimaryIndex(index + 3) % csString.length();
		SwapCharacter(csString, iPosA, iPosB);
	}
	return csString;
}

};

int main(int argc, char **argv)
{
	crypt C;
	string cs = C.Encrypt("piehole");
	string ds = C.Decrypt(cs);
	
	cout << cs << endl;
	cout << ds << endl;
	
	return 0;
}

Go version by mrngm :

package main

import (
	"fmt"
)

func Encrypt(s string) string {
	encLen := len(s)
	encBytes := []byte(s)
	for i := 0; i < encLen; i++ {
		oidx := offsetIndex(i + 3)
		newpos := oidx % encLen
		//		fmt.Printf("i: %d (oidx: %d), newpos: %d\n", i, oidx, newpos)
		encBytes[newpos], encBytes[i] = encBytes[i], encBytes[newpos]
	}
	return string(encBytes)
}

func Decrypt(s string) string {
	decLen := len(s)
	decBytes := []byte(s)
	for i := decLen - 1; i >= 0; i-- {
		oidx := offsetIndex(i + 3)
		newpos := oidx % decLen
		//	fmt.Printf("i: %d (oidx: %d), newpos: %d\n", i, oidx, newpos)
		decBytes[newpos], decBytes[i] = decBytes[i], decBytes[newpos]