Help in code to crack a symantic key for a TEA algorithm

[elsa87]

hi everyone..i need to crack a symmetric key by implementing a method called CrackSymmetricKey
I must use the TEA encryption algorithm below:

union myMsgType{
		unsigned long textConverted[2];
		char text[9];
};

class TEA_Algorithm  
{
public:
	void CrackSymmetricKey(union myMsgType plaintext, union myMsgType ciphertext);
	void Decrypt(unsigned long k[], unsigned long ciphertext[], unsigned long plaintext[]);
	void Encrypt(unsigned long k[], unsigned long plaintext[], unsigned long ciphertext[]);
	TEA_Algorithm() {};
	virtual ~TEA_Algorithm() {};

};

As input, im given the following ciphertext and i need to find the secret key that has been used to obtain this ciphertext, and hence, deduce the original plaintext.
// myCiphertext.textConverted[0] = 2022673309;
// myCiphertext.textConverted[1] = 3810199360;

#include "stdafx.h" 
#include <iostream>
#include <string.h>
using namespace std;

#include "TEA_Algorithm.h"

void TEA_Algorithm::Encrypt(unsigned long k[], unsigned long plaintext[], unsigned long ciphertext[])
{
unsigned long y = plaintext[0], z = plaintext[1];
	unsigned long delta = 0x9e3779b9, sum = 0; int n;
	for (n= 0; n < 32; n++) {
		sum += delta;
		y += ((z << 4) + k[0]) ^ (z+sum) ^ ((z >> 5) + k[1]);        
		z += ((y << 4) + k[2]) ^ (y+sum) ^ ((y >> 5) + k[3]);        
	}
	ciphertext[0] = y;  ciphertext[1] = z; 

}

void TEA_Algorithm::Decrypt(unsigned long k[], unsigned long ciphertext[], unsigned long plaintext[])
{
unsigned long y = ciphertext[0], z = ciphertext[1];
	unsigned long delta = 0x9e3779b9, sum = delta << 5;  int n;
	for (n= 0; n < 32; n++) {
		z -= ((y << 4) + k[2]) ^ (y + sum) ^ ((y >> 5) + k[3]);
		y -= ((z << 4) + k[0]) ^ (z + sum) ^ ((z >> 5) + k[1]);
		sum -= delta;
	}
	plaintext[0] = y; plaintext[1] = z;
}

void TEA_Algorithm::CrackSymmetricKey(union myMsgType plaintext, union myMsgType ciphertext)
{
	void CrackSymmetricKey(union c);
/* 
 what should i write here if this is what's given:
	plaintext:= security
	ciphertext: 	
		myCiphertext.textConverted[0] = 2022673309;
		myCiphertext.textConverted[1] = 3810199360;

	additional information: key[0]=key[1]=k[2]=k[3]
 and you're asked to determine what is the secret key that 
 has been used to encrypt this plaintext.
*/

}

plz help..i know i should make a loop inside but im very weak in programming

[Salem]

> .i know i should make a loop inside but im very weak in programming
You'd better be a demon cryptographer then.
Without one or the other, this seems a hard problem.

[skatamatic]

Hah. There's whole courses on stuff like this. I'd sugguest you take one if you really plan on writing this. Or pull your hair out!

[al7ooryah]

hi ..
am having the same problem .. and the doctor asked us to complete the crack .. if any body know any thing that may help me in it plz plz ..

[ArkM]

Is it a joke? Are you sure that it's possibble to crack a cipher if you can compose some method name like

class CrackAllTheWorld {
public:
    bool InvokeSuperCracker(void* ciphertext) {
           return true;
    }
};

Better download this article on TEA cryptanalysis topic: http://cs.ua.edu/SecurityResearchGroup/VRAndem.pdf
(~1.73Mb). May be it helps...