Solved it!! Thought of sharing the solution here, it might be helpful to someone.

Qt Code: 
  1. // Open the certificate store to be searched.
  2.     HCERTSTORE hSystemStore = CertOpenStore((LPCSTR)(CERT_STORE_PROV_SYSTEM),  0, NULL,
  3.                                  CERT_SYSTEM_STORE_LOCAL_MACHINE, L"MY");
  4.  
  5.     CRYPT_DATA_BLOB dataBlob = {0};
  6.     QString password("password"); // your password for the cretificate and private key goes here
  7.  
  8.     if(PFXExportCertStoreEx(hSystemStore, &dataBlob, password.toStdWString().c_str(), NULL,
  9.                                 EXPORT_PRIVATE_KEYS | REPORT_NOT_ABLE_TO_EXPORT_PRIVATE_KEY | REPORT_NO_PRIVATE_KEY))
  10.     {
  11.         if (dataBlob.cbData > 0)
  12.         {
  13.             dataBlob.pbData = (BYTE*)malloc(dataBlob.cbData);
  14.             if (PFXExportCertStoreEx(hSystemStore, &dataBlob, password.toStdWString().c_str(), NULL,
  15.                                         EXPORT_PRIVATE_KEYS | REPORT_NOT_ABLE_TO_EXPORT_PRIVATE_KEY | REPORT_NO_PRIVATE_KEY))
  16.             {
  17.                 EVP_PKEY *pkey;
  18.                 X509 *cert;
  19.                 STACK_OF(X509) *ca = NULL;
  20.                 PKCS12 *p12;
  21.                 int i;
  22.                 CRYPTO_malloc_init();
  23.                 OpenSSL_add_all_algorithms();
  24.                 SSLeay_add_all_algorithms();
  25.                 ERR_load_crypto_strings();
  26.  
  27.                 BIO* input = BIO_new_mem_buf((void*)dataBlob.pbData, dataBlob.cbData);
  28.                 p12 = d2i_PKCS12_bio(input, NULL);
  29.  
  30.                 PKCS12_parse(p12, password.toStdString().c_str(), &pkey, &cert, &ca);
  31.                 PKCS12_free(p12);
  32.  
  33.                 if (cert)
  34.                 {
  35.                     BIO *boCert = BIO_new( BIO_s_mem() );
  36.  
  37.                     PEM_write_bio_X509(boCert, cert);
  38.                     if (ca && sk_X509_num(ca))
  39.                     {
  40.                         for (i = 0; i < sk_X509_num(ca); i++)
  41.                         {
  42.                             PEM_write_bio_X509(boCert, sk_X509_value(ca, i));
  43.                         }
  44.                     }
  45.                     char *certStr;
  46.                     long len = BIO_get_mem_data(boCert, &certStr);
  47.  
  48.                     QSslCertificate localCertificate(QByteArray::fromRawData(certStr, len));
  49.                     mySslSocket->setLocalCertificate(localCertificate);
  50.  
  51.                     BIO_free_all(boCert);
  52.                 }
  53.  
  54.                 if (pkey)
  55.                 {
  56.                     BIO *bo = BIO_new( BIO_s_mem() );
  57.                     PEM_write_bio_PrivateKey(bo, pkey, NULL, (unsigned char*)(password.toStdString().c_str()), password.length(), NULL, (char*)(password.toStdString().c_str()));
  58.  
  59.                     char *p;
  60.                     long len = BIO_get_mem_data(bo, &p);
  61.  
  62.                     QSslKey key(QByteArray::fromRawData(p, len), QSsl::Rsa);
  63.                     mySslSocket->setPrivateKey(key);
  64.                     BIO_free_all(bo);
  65.                 }
  66.                free(dataBlob.pbData);
  67.             }
  68.         }
  69.     }
  70.  
  71.     if(hSystemStore)
  72.         CertCloseStore(hSystemStore, 0);
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Thanks, new to the forum so didn't knew how to do that