Problem While Using RSA for encryption

[shawn gibson]

PROBLEM :I had been trying to encrypt and decrypt data using RSA algorithm it works well till 80 characters but after that it shows abnormal program termination

exact error message :Abnormal program Termination

Code Sample:

#include "pch.h"
#include "md5.h"
#include "sha.h"
#include "ripemd.h"
#include "files.h"
#include "rng.h"
#include "hex.h"
#include "gzip.h"
#include "default.h"
#include "rsa.h"
#include "randpool.h"
#include "ida.h"
#include "base64.h"
#include "socketft.h"
#include "dsa.h"
#include "rsa.h"
#include "osrng.h"
#include "wait.h"
#include "fips140.h"

#include "validate.h"
#include "bench.h"

#include <iostream>
#include <time.h>

#if defined(_WIN32) || defined(__CYGWIN__)
#include <windows.h>
#endif

#if (_MSC_VER >= 1000)
#include <crtdbg.h>  // for the debug heap
#endif

#if defined(__MWERKS__) && defined(macintosh)
#include <console.h>
#endif

USING_NAMESPACE(CryptoPP)
USING_NAMESPACE(std)

const int MAX_PHRASE_LENGTH=250;

void GenerateRSAKey(unsigned int keyLength, const char *privFilename, const char *pubFilename, const char *seed)
{
 RandomPool randPool;
 randPool.Put((byte *)seed, strlen(seed));

 RSAES_OAEP_SHA_Decryptor priv(randPool, keyLength);
 HexEncoder privFile(new FileSink(privFilename));
 priv.DEREncode(privFile);
 privFile.MessageEnd();

 RSAES_OAEP_SHA_Encryptor pub(priv);
 HexEncoder pubFile(new FileSink(pubFilename));
 pub.DEREncode(pubFile);
 pubFile.MessageEnd();
}

string RSAEncryptString(const char *pubFilename, const char *seed, const char *message)
{
 FileSource pubFile(pubFilename, true, new HexDecoder);
 RSAES_OAEP_SHA_Encryptor pub(pubFile);

 RandomPool randPool;
 randPool.Put((byte *)seed, strlen(seed));

 string result;
 StringSource(message, true, new PK_EncryptorFilter(randPool, pub, new HexEncoder(new StringSink(result))));
 return result;
}

string RSADecryptString(const char *privFilename, const char *ciphertext)
{
 FileSource privFile(privFilename, true, new HexDecoder);
 RSAES_OAEP_SHA_Decryptor priv(privFile);

 string result;
 StringSource(ciphertext, true, new HexDecoder(new PK_DecryptorFilter(priv, new StringSink(result))));
 return result;
}

void main() {

  char seed[1024], privFilename[128], pubFilename[128];
  unsigned int keyLength;
  char message[1024];

  cout << "Key length in bits: ";
  cin >> keyLength;

  cout << "\nSave private key to file: ";
  cin >> privFilename;

  cout << "\nSave public key to file: ";
  cin >> pubFilename;

  cout << "\nRandom Seed: ";
  ws(cin);
  cin.getline(seed, 1024);

  cout<< "\nRandom Seed:1 " << seed;
  GenerateRSAKey(keyLength, privFilename, pubFilename, seed);
  cout<< "\nRandom Seed:2 " << seed; 
  // char privFilename[128], pubFilename[128];
  // char seed[1024], message[1024];

  // cout << "Private key file: ";
  // cin >> privFilename;

  // cout << "\nPublic key file: ";
  // cin >> pubFilename;

  // cout << "\nRandom Seed: ";
  // ws(cin);
  // cin.getline(seed, 1024);

  cout << "\nMessage: ";
  cin.getline(message, 1024);

  cout<< "\nRandom Seed:3 " << seed; 
  string ciphertext = RSAEncryptString(pubFilename, seed, message);
  cout<< "\nRandom Seed:4 " << seed; 
  cout << "\nCiphertext: " << ciphertext << endl;

  string decrypted = RSADecryptString(privFilename, ciphertext.c_str());
  cout << "\nDecrypted: " << decrypted << endl;
}

Compiler And Platform Used :Windows(2000) ,crypto++ ver 5and VC++ compiler

I will be very thankful if anyone can help me out

Regards,

Shawn

 

 

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