TEA encryption algorithm

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void encipher(const unsigned long *const v,unsigned long *const w,
   const unsigned long * const k)
{
   register unsigned long       y=v[0],z=v[1],sum=0,delta=0x9E3779B9,n=32;

   while(n-->0)
      {
      y += (z << 4 ^ z >> 5) + z ^ sum + k[sum&3];
      sum += delta;
      z += (y << 4 ^ y >> 5) + y ^ sum + k[sum>>11 & 3];
      }

   w[0]=y; w[1]=z;
}

void decipher(const unsigned long *const v,unsigned long *const w,
   const unsigned long * const k)
{
   register unsigned long       y=v[0],z=v[1],sum=0xC6EF3720,
				delta=0x9E3779B9,n=32;

   /* sum = delta<<5, in general sum = delta * n */

   while(n-->0)
      {
      z -= (y << 4 ^ y >> 5) + y ^ sum + k[sum>>11 & 3];
      sum -= delta;
      y -= (z << 4 ^ z >> 5) + z ^ sum + k[sum&3];
      }
   
   w[0]=y; w[1]=z;
}

unsigned long ConvertStringToUInt(char *input)
{
	unsigned long output=0;
	
    output =  ((unsigned long)input[0]);
    output += ((unsigned long)input[1] << 8);
    output += ((unsigned long)input[2] << 16);
    output += ((unsigned long)input[3] << 24);

	return output;
}

void ConvertUIntToString(unsigned long input,char *szOutput)
{
	char tempChar;
	char szReturn[64]={0};

	tempChar = (char)input & 0xFF;
	szReturn[0]=tempChar;
	tempChar = (char)((input >> 8) & 0xFF);
	szReturn[1]=tempChar;
	tempChar = (char)((input >> 16) & 0xFF);
	szReturn[2]=tempChar;
	tempChar = (char)((input >> 24) & 0xFF);
	szReturn[3]=tempChar;

	sprintf(szOutput,"%s",szReturn);
}
void Decrypt(char* data, char *key, char*decrypted)
{
	unsigned long tempData[2];
	unsigned long returnData[2];
	char szTemp[128]={0};
	unsigned long longKey[64];
	unsigned int i;

	//printf(">>>>>>%d %s\n",strlen(key),key);
	
	for(i=0;i<64;i++){longKey=0;}
	for(i=0;i<strlen(key);i++)
	{
		longKey=key;
	}

	for(i=0;i<strlen(data);i+=8)
	{
		strncpy(szTemp,data+i,4);
		tempData[0]=ConvertStringToUInt(szTemp);
		strncpy(szTemp,data+i+4,4);
		tempData[1]=ConvertStringToUInt(szTemp);

		printf("> (%c-%c)\n",tempData[0],tempData[1]);
		decipher(tempData,returnData,longKey);		
		printf("> (%c-%c)\n",returnData[0],returnData[1]);

	}
}

void Encrypt(char* data,char *key,char* encrypted)
{
	unsigned long tempData[2];
	unsigned long tempData2[2];
	unsigned long returnData[2];

	char szTemp[128]={0};
	unsigned long longKey[64];
	unsigned int i;

	//printf(">>>>>>%d %s\n",strlen(key),key);
	if(strlen(data)%2!=0)
	{
		data[strlen(data)]='\0';
	}

	for(i=0;i<64;i++){longKey=0;}
	for(i=0;i<strlen(key);i++)
	{
		longKey=key;
	}

	for(i=0;i<strlen(data);i+=2)
	{
		tempData[0]=data;
		tempData[1]=data[i+1];
		
		encipher(tempData,returnData,longKey);
		printf("> (%c-%c)\n",returnData[0],returnData[1]);
		decipher(returnData,tempData2,longKey);
		printf("> (%c-%c)\n",tempData2[0],tempData2[1]);

		ConvertUIntToString(returnData[0],szTemp);
		strcat(encrypted,szTemp);
		ConvertUIntToString(returnData[1],szTemp);
		strcat(encrypted,szTemp);
	}
}

void main()
{
	char szEncrypted[128]={0};
	char szDecrypted[128]={0};
	char szString[128]={0};
	char szKey[64]="thekey";


	scanf("%s",szString);	

	Encrypt(szString,szKey,szEncrypted);

	printf("Encrypted:%s\n",szEncrypted);

	Decrypt(szEncrypted,szKey,szDecrypted);

	printf("Decrypted:%s\n",szDecrypted);

}