Debugging C++ AES Encryption Wrapper Class - c++

Question

I need to add AES encryption functionality to my C++ project. So far I am trying to write a wrapper class for Code project: C++ Implementation of AES++ which is to have the following functions:
char* Encrypt(string& InputData); //takes plain text and returns encrypted data
char* Decrypt(string& InputData); //takes encrypted data and returns plain text
But when I test my code only the first 32 bytes of the data are encrypted and decrypted.
The final line of the output is:-
This is Encryption Test My name
What is making it miss the rest of the string? What am I missing?
#include "Rijndael.h"
#include <iostream>
#include <string>
using namespace std;
string LenMod(string Input);
char* Encrypt(string& InputData)
{
try
{
InputData = LenMod(InputData);
char* OutputData = (char*)malloc(InputData.size() + 1);
memset(OutputData, 0, sizeof(OutputData));
CRijndael AESEncrypter;
AESEncrypter.MakeKey("HiLCoE School of Computer Science and Technology",CRijndael::sm_chain0, 16 , 16);
AESEncrypter.Encrypt(InputData.c_str(), OutputData, sizeof(InputData), CRijndael::ECB);
return OutputData;
}
catch(exception e)
{
cout<<e.what();
return NULL;
}
}
char* Decrypt(string& Input)
{
try
{
Input = LenMod(Input);
char* Output = (char*)malloc(Input.size() + 1);
memset(Output, 0, sizeof(Output));
CRijndael AESDecrypter;
AESDecrypter.MakeKey("HiLCoE School of Computer Science and Technology",CRijndael::sm_chain0, 16, 16);
AESDecrypter.Decrypt(Input.c_str(), Output, sizeof(Input), CRijndael::ECB);
return Output;
}
catch(exception e)
{
cout<<e.what();
return NULL;
}
}
string LenMod(string Input)
{
while(Input.length() % 16 != 0)
Input += '\0';
return Input;
}
int main()
{
string s = "This is Encryption Test My name is yohannes tamru i am a computer science student";
//cout<<LengthMod(s)<<endl;
string temp1(Encrypt(s));
string temp2(Decrypt(temp1));
cout<<temp1<<endl<<endl<<temp2<<endl;
system("pause");
return 0;
}