How encrypt and decrypt several values in a row - c++

Question

In my programm I use crypto++ library.
I have so struct:
struct crypt_struct{
//consists of encrypted data
string name1;
string name2;
string name3;
}
struct decrypt_struct{
//consists of decrypted data
int name1;
string name2;
double name3;
}
I have encrypt function:
crypt_struct encrypt(decrypt_struct struct_in) {
//Key and IV setup
//AES encryption uses a secret key of a variable length (128-bit, 196-bit or 256-
//bit). This key is secretly exchanged between two parties before communication
//begins. DEFAULT_KEYLENGTH= 16 bytes
byte key[CryptoPP::AES::DEFAULT_KEYLENGTH], iv[CryptoPP::AES::BLOCKSIZE];
memset(key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH);
memset(iv, 0x00, CryptoPP::AES::BLOCKSIZE);
//output encrypt struct
crypt_struct struct_out;
//encrypt text
string ciphertext;
CryptoPP::AES::Encryption aesEncryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
CryptoPP::CBC_Mode_ExternalCipher::Encryption cbcEncryption(aesEncryption, iv);
CryptoPP::StreamTransformationFilter stfEncryptor(cbcEncryption, new CryptoPP::StringSink(ciphertext));
//int name1
stfEncryptor.Put(reinterpret_cast<const unsigned char*> ((to_string(struct_in.name1)).c_str()), (to_string(struct_in.name1)).length() + 1);
stfEncryptor.MessageEnd();
struct_out.name1 = ciphertext;
cout << ciphertext << endl;
ciphertext.clear();
//string name2
stfEncryptor.Put(reinterpret_cast<const unsigned char*> (struct_in.name2.c_str()), struct_in.name2.length() + 1);
stfEncryptor.MessageEnd();
struct_out.name2 = ciphertext;
cout << ciphertext << endl;
ciphertext.clear();
//double name3
stfEncryptor.Put(reinterpret_cast<const unsigned char*> ((to_string(struct_in.name3)).c_str()), (to_string(struct_in.name3)).length() + 1);
stfEncryptor.MessageEnd();
struct_out.name3 = ciphertext;
cout << ciphertext << endl;
ciphertext.clear();
return struct_out;
}
And decrypt function:
decrypt_struct decrypt(crypt_struct struct_in)
{
//Key and IV setup
//AES encryption uses a secret key of a variable length (128-bit, 196-bit or 256-
//bit). This key is secretly exchanged between two parties before communication
//begins. DEFAULT_KEYLENGTH= 16 bytes
byte key[CryptoPP::AES::DEFAULT_KEYLENGTH], iv[CryptoPP::AES::BLOCKSIZE];
memset(key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH);
memset(iv, 0x00, CryptoPP::AES::BLOCKSIZE);
//
// Decrypt
//
decrypt_struct struct_out;
string decryptedtext;
CryptoPP::AES::Decryption aesDecryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption(aesDecryption, iv);
CryptoPP::StreamTransformationFilter stfDecryptor(cbcDecryption, new CryptoPP::StringSink(decryptedtext));
stfDecryptor.Put(reinterpret_cast<const unsigned char*>(struct_in.name1.c_str()), struct_in.name1.length());
struct_out.name1= atoi(decryptedtext.c_str());
stfDecryptor.MessageEnd();
decryptedtext.clear();
stfDecryptor.Put(reinterpret_cast<const unsigned char*>(struct_in.name2.c_str()), struct_in.name2.length());
struct_out.name2= atoi(decryptedtext.c_str());
stfDecryptor.MessageEnd();
decryptedtext.clear();
stfDecryptor.Put(reinterpret_cast<const unsigned char*>(struct_in.name3.c_str()), struct_in.name3.length());
struct_out.name3= atoi(decryptedtext.c_str());
stfDecryptor.MessageEnd();
decryptedtext.clear();
return struct_out;
}
If I try encrypt only one variable, then everything is decrypted correctly. But if I try to encrypt several variables at the same time, then an error occurs. And moreover, when encrypting the variable int type, the same error occurs. With what it can be connected, is there anyone's idea?
It seems to me that perhaps the reason is that at a time this function can only encrypt one line.

Answer 1

The problem was this:
The matter is that in the source code of this library, when decrypting, the c_str() function is used. Those:
stfDecryptor.Put(reinterpret_cast<const unsigned char*> (struct_in.name1.c_str()), struct_in.name1.size());
The official documentation says:
The pointer obtained from c_str() may only be treated as a pointer to a null-terminated character string if the string object does not contain other null characters.
In the encryption function, a zero character is added to the string, and when we try to decrypt, by the c_str() function, we trim our string with the first zero character.
But, in the standard with с++ 11, an analogous function was added that performs the same action as the data() function, except that it does not take into account the null character.
As a result, I received:
stfDecryptor.Put(reinterpret_cast<const unsigned char*> (struct_in.name1.data()), struct_in.name1.size());
Also, it was important if you encrypt first name1, then name2, and name3. That and decrypt you should in the same sequence.