Problem decrypting [Solved]

[Sixx93]

Hi all, i'm trying to do a simple crypter for strings. With the Crypt function i have no problem:

int lunghezza;               //As globals
double valori[20];           

char* AltCrypt(char* string)
{
	lunghezza = strlen(string);
	char* tempstring = new char[lunghezza + 1];

	for (int j=0; j<lunghezza; j++)
	{	 valori[j] = atof(&string[j]);
		
		tempstring[j] = string[j] + string[j+1];
		j++;
	}

	tempstring[lunghezza/2] = 0;
	return tempstring;
}

In the console i print the crypted string and it's all good. When i try to Decrypt it, the console doesn't print me anything. That's my function to Decrypt:

char* AltDecrypt(char* string)
{
	lunghezza = strlen(string);
	
	char* tempstring = new char[(lunghezza*2) + 1];

	for (int j=0; j<lunghezza; j++)
	{	
		tempstring[j] = valori[j];
		tempstring[j+1] = string[j] - valori[j];
		
	}

	tempstring[lunghezza*2] = 0;
	return tempstring;
}

And finally this is how i call them in the main:

        cout<<"Alt-crypting: Hi man!"<<endl;
	char* done = AltCrypt("Hi man!");
	cout<<done;
	cout<<"\n\nAlt Decrypting: "<<AltDecrypt(done);

That's the result:

I tryed to follow the debug step by step with the breakpoints but when the compiler arrives at the Decrypt function it stops and asks me for a file(ftol2.asm). I tryed to google it but all says that it's not a problem, u can easily avoid it by put the breakpoint after that instruction. So, can anyone help me? ty in advance

[Hell_Demon]

Re-read over those two functions and try doing them in your head with say 2 numbers, they don't make sense .-.

[Sixx93]

Re-read over those two functions and try doing them in your head with say 2 numbers, they don't make sense .-.

for me it has sense .-. i only add the j element with the next one so i can have a crypted string with half size of the original. maybe i have to explain the whole code :\ so u all can understand better

[Nico]

for me it has sense .-. i only add the j element with the next one so i can have a crypted string with half size of the original. maybe i have to explain the whole code :\ so u all can understand better

But you change the number of the next thing so if you decrypt it, it uses another number.

[Sixx93]

But you change the number of the next thing so if you decrypt it, it uses another number.

no, because the original one is stored in the array

[Hell_Demon]

crypt has 2x j++

[Sixx93]

crypt has 2x j++

yes, because the j+1 element is added with the j's one, so i have to jump of 2 steps

[Hell_Demon]

Make an array of a few numbers and check the array values after each step, you'll probably figure out whats going wrong then..

[Sixx93]

Make an array of a few numbers and check the array values after each step, you'll probably figure out whats going wrong then..

i worked on my 2 functions, i changed something that could be wrong, now i get a decrypted string, but it's not right, it isn't the original. these are the new ones:

int lunghezza;
int valori[20];

char* AltCrypt(char* string)
{
	lunghezza = strlen(string);
	char* tempstring = new char[lunghezza + 1];

	for (int j=0; j<lunghezza; j+=2)
	{	
		valori[j] = atoi(&string[j]);
		tempstring[j] = string[j] + string[j+1];
	}

	tempstring[lunghezza/2] = 0;
	return tempstring;
}

char* AltDecrypt(char* string)
{
	char* tempstring = new char[lunghezza+1];

	for (int j=0; j<lunghezza; j+=2)
	{	
		itoa(valori[j],&tempstring[j],10);
		tempstring[j+1] = string[j] - tempstring[j];
	
	}

	tempstring[lunghezza] = 0;
	return tempstring;
}

[ғᴜᴋᴏᴊʀ]

i worked on my 2 functions, i changed something that could be wrong, now i get a decrypted string, but it's not right, it isn't the original. these are the new ones:

int lunghezza;
int valori[20];

char* AltCrypt(char* string)
{
	lunghezza = strlen(string);
	char* tempstring = new char[lunghezza + 1];

	for (int j=0; j<lunghezza; j+=2)
	{	
		valori[j] = atoi(&string[j]);
		tempstring[j] = string[j] + string[j+1];
	}

	tempstring[lunghezza/2] = 0;
	return tempstring;
}

char* AltDecrypt(char* string)
{
	char* tempstring = new char[lunghezza+1];

	for (int j=0; j<lunghezza; j+=2)
	{	
		itoa(valori[j],&tempstring[j],10);
		tempstring[j+1] = string[j] - tempstring[j];
	
	}

	tempstring[lunghezza] = 0;
	return tempstring;
}

I suggest just listening to Wesley, he knows what he's talking about.

[zhaoyun333]

Many problems in your code.
First off

valori[j] = atoi(&string[j]);

This dosen't do anything at all. Try outputting it in your code and you'll get 0 everytime. Do you know atoi does? It changes a STRING to an integer and I dont even know what you're trying to do.

2nd issue

itoa(valori[j],&tempstring[j],10);

This piece of code is jsut as useless. itoa takes the value of the first parameter and stores it in a string. However, you're taking valori[j] and trying to store it in the address of the character

Perhaps if you could try to explain your encryption method we can help you

[flameswor10]

https://www.mpgh.net/forum/207-combat...n-methods.html

[Sixx93]

Many problems in your code.
First off

valori[j] = atoi(&string[j]);

This dosen't do anything at all. Try outputting it in your code and you'll get 0 everytime. Do you know atoi does? It changes a STRING to an integer and I dont even know what you're trying to do.

2nd issue

itoa(valori[j],&tempstring[j],10);

This piece of code is jsut as useless. itoa takes the value of the first parameter and stores it in a string. However, you're taking valori[j] and trying to store it in the address of the character

Perhaps if you could try to explain your encryption method we can help you

i used atoi to get the ascii code of each char but i see that this isn't the right method... anyway my idea is to convert all the chars in the string to the ascii code and create a new (crypted) string wich will have as first char the ascii value equal to the sum of the first and second char of the original; as second the sum of the 3rd and the 4th of the original, etc etc... i used itoa to try to convert the number to the char equivalent in ascii. hope is all clear.

@flameswor10 ty for your 2 functions, they inspired me for making my ones ( not this ones xD )

struct Command
{	public:
		char* string;
		 bool a_crypted;
		void Crypt();
		void Decrypt();

	private:
		int* RandomNum(int);
		int* numb;
		
};



int* Command::RandomNum(int times)
{	int lowest = 0, highest = 65;
	int* numbers = new int[times+1];
	for(int j=0; j<times; j++)
	{
    int random_integer; 
    int range=(highest-lowest)+1; 
        random_integer = lowest+int(range*rand()/(RAND_MAX + 1.0)); 
		numbers[j] = random_integer;
	}
	return numbers;
}

void Command::Crypt()
{	a_crypted = true;
	int length = strlen(string);
	char* tempstring = new char[length + 1];
	numb = new int[length+1];
	numb = RandomNum(length);

	for (int j=0; j<length; j++)
	{
		int KeyStep = numb[j] + j;
		tempstring[j] = string[j] + KeyStep;
		
	}

	tempstring[length] = 0;
	string = tempstring;
}
void Command::Decrypt()
{	
	int length = strlen(string);
	char* tempstring = new char[length + 1];
if(a_crypted == false)
{
	numb = new int[length+1];
	numb = RandomNum(length);
}
	for (int j=0; j<length; j++)
	{
		int KeyStep = numb[j] + j;
		tempstring[j] = string[j] - KeyStep;
		
	}

	tempstring[length] = 0;
	string = tempstring;
}

for a bug of your (again xD) RandomNum function, it works very well i mean, that function works, but it generate every time the same random numbers

After i did this encryption method i thought i wanted to write a function to crypt a string modifying the length of it, so here they are xD the only problem is that they don't work xD

[zhaoyun333]

You need to seed the random function:

#include <time.h>

int main(void){

srand(time(NULL));

/*
blahblah
*/

}

[Sixx93]

You need to seed the random function:

#include <time.h>

int main(void){

srand(time(NULL));

/*
blahblah
*/

}

no it works very well .-.