Beispiel zur Erstellung:
hallo ^ servus ^ moin = xorUnit

Beispiel zur Wiederherstellung:
moin ^ hallo ^ xorUnit = servus

Allerdings geht dies nicht und ich erhalte nur "serv", da mir die Länge da irgendwie Schwierigkeiten bereitet. Ich hoffe Ihr könnt mit helfen

#include <iostream>
#include <iomanip>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <vector>

using namespace std;

struct UNIT
{
   int size;
   char *content;
};

UNIT XOR( vector<UNIT> list )
{
  char* unit;
  char* temp;

  UNIT xorUnit;   
  int unitLength = 0;
  int maxLength = 0;
  int minLength = 0;
  int bigger = 0;

  for( int i = 0; i < list.size(); i++ )
  {
    unitLength = list[i].size;

    if( minLength == 0 && maxLength == 0 ) 
    {
      maxLength = unitLength;
    }
    else if( unitLength > maxLength )
    {
      minLength = maxLength;
      maxLength = unitLength;
      bigger = 1;
    }
    else if( unitLength < maxLength )
    {
      minLength = unitLength; 
      bigger = 0;
    }
    printf("bigger: %d\n", bigger);
    printf("MaxLänge: %d\n", maxLength);
    printf("MinLänge: %d\n", minLength);   

    temp = new char[maxLength];

    for(int j = 0; j < minLength; j++)
    {
      temp[j] = list[i].content[j] ^ unit[j];
    }
    for(int j = minLength; j < maxLength; j++)
    {
      temp[j] = list[i].content[j];
    }
    unit = temp;
  }

  xorUnit.content = unit;
  if( bigger == 0 ) {
    xorUnit.size = minLength;
  } else {
    xorUnit.size = maxLength;
  }
  bigger = 0;

  return xorUnit;
}

int main(int argc,char **argv) {      
  int i;

  vector<UNIT> list;
  vector<UNIT> backupList;

  //Eingabeunits
  UNIT input1;
  UNIT input2;
  UNIT input3;

  UNIT xorUnit;  
  UNIT output;

  input1.size = 5;
  input1.content = "hallo";    
  input2.size = 6;
  input2.content = "servus";  
  input3.size = 4;
  input3.content = "moin";

  list.push_back( input1 );
  list.push_back( input2 );  
  list.push_back( input3 );  

  for( i = 0; i < list.size(); i++ )
  {
     output = list[i];
     printf("Vector(%d): %s %d\n", i, output.content, output.size);
  }

  xorUnit = XOR( list );
  printf("XOR: %s %d\n\n\n", xorUnit.content, xorUnit.size);

  backupList.push_back( input3 );
  backupList.push_back( input1 );  
  backupList.push_back( xorUnit );  

  for( i = 0; i < backupList.size(); i++ )
  {
     output = backupList[i];
     printf("Vector(%d): %s %d\n", i, output.content, output.size);
  } 

  xorUnit = XOR( backupList );
  printf("XOR: %s %d\n", xorUnit.content, xorUnit.size); 

  return 0;
}

#include <iostream> 
#include <iomanip> 
#include <stdlib.h> 
#include <stdio.h> 
#include <string.h> 
#include <vector> 
#include <algorithm>

using namespace std; 

string XOR(vector<string> list) 
{ 
	string xorUnit;  
	for( int i = 0; i < list.size(); i++ ) 
	{ 
		string unit = list[i];
		if(unit.size() > xorUnit.size())
			xorUnit.resize(unit.size(), 0);

		transform(unit.begin(), unit.end(), xorUnit.begin(), xorUnit.begin(), bit_xor<char>());
	}
	return xorUnit; 
} 

int main(int argc, char **argv) 
{
	string input1 = "hallo";
	string input2 = "servus";
	string input3= "moin";

	vector<string> list;
	list.push_back(input1); 
	list.push_back(input2);   
	list.push_back(input3);   

	for(int i = 0; i < list.size(); i++) 
	{ 
		string output = list[i]; 
		printf("Vector(%d): %s %d\n", i, output.c_str(), output.size()); 
	} 

	string xorUnit = XOR(list); 

	vector<string> backupList; 
	backupList.push_back(input3); 
	backupList.push_back(input1);   
	backupList.push_back(xorUnit);   

	for(int i = 0; i < backupList.size(); i++) 
	{ 
		string output = backupList[i]; 
		printf("Vector(%d): %s %d\n", i, output.c_str(), output.size()); 
	} 

	xorUnit = XOR( backupList); 
	printf("XOR: %s %d\n", xorUnit.c_str(), xorUnit.size()); 

	return 0; 
}

Hoffe das "transform" passt so, konnte das nie wirklich gut...

#include <string.h>

durch

#include <string>

ersetzt wird, ist es fast perfekt

Ich sehe gerade die "printf"s *grusel*