| FBB::OSymCryptStream(3bobcat) | Symmetric en- and decryption | FBB::OSymCryptStream(3bobcat) |
FBB::OSymCryptStream - std::ostream performing symmetric en/decryption
#include <bobcat/osymcryptstream>
Linking option: -lbobcat -lcrypto
FBB::OSymCryptStream objects can be used to encrypt or decrypt information, that is available on separate std::istream streams.
The class OSymCryptStream is a class template, using a FBB::CryptType template non-type parameter. Objects of the class FBB::OSymCryptStream<FBB::ENCRYPT> encrypt the information they receive, objects of the class FBB::OSymCryptStream<FBB::DECRYPT> decrypt the information they receive.
All symmetric encryption methods defined by the OpenSSL library that can be selected by name may be used to en/decrypt information. To select a particular encryption method an identifier is passed to the constructor. E.g., "aes-256-gcm". For the currently supported cipher algorithms issue the command
openssl list -cipher-algorithms
OSymCryptStream objects read the information to en/decrypt from an external source (e.g., from std::istream objects). The characters that are encrypted or decrypted by OSymCryptStream objects are written to std::ostream objects which are at construction-time specified as ostream references or by filename.
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
FBB::OSymCryptStreambuf (private),
std::istream
If the construction fails an exception is thrown, mentioning the openssl function that failed to complete (see also errorMsg below).
The move constructor is available, the copy constructor and assignment operators are not available,
Since the class is publicly derived from std::ostream, all std::ostream members can be used.
The latter two functions throw exceptions if cipherName does not contain the name of a supported cipher algorithm.
Activating those lines will not result in processing the in stream twice.
//in.seekg(0); // when activated, this won’t
//enc << in.rdbuf(); // be processed due to ’<< eoi’
#include <iostream>
#include <fstream>
#include <string>
#include <bobcat/osymcryptstream>
using namespace std;
using namespace FBB;
int main(int argc, char **argv)
try
{
if (argc == 1)
{
cout << "arg[1]: e - encrypt, d - decrypt,\n"
"arg[2]: file to process, arg[3]: processed file\n";
return 0;
}
string key = "0123456789abcdef0123456789abcdef";
cout << "encryption key ? ";
cin >> key;
while (key.size() < 32)
key += key;
string iv = " 0123456789ab" "456";
char cipherName[] =
"AES-256-GCM"
//"AES-256-CBC"
;
ifstream in{ argv[2] };
ofstream out{ argv[3] };
if (*argv[1] == ’e’)
{
OSymCryptStream<ENCRYPT> enc{ out, cipherName, key, iv, 100 };
// comment out the above statement and uncomment the next
// to use the constructor expecting a string as 1st arg:
// OSymCryptStream<ENCRYPT> enc{ argv[3], cipherName, key,
// iv, 100 };
enc << in.rdbuf() << eoi;
//in.seekg(0); // when activated, this won’t
//enc << in.rdbuf(); // be processed due to ’<< eoi’
}
else
{
OSymCryptStream<DECRYPT> decrypt{ out, cipherName, key,
iv, 100 };
// comment out the above statement and uncomment the next
// to use the constructor expecting a string as 1st arg:
// OSymCryptStream<DECRYPT> decrypt{ argv[3], cipherName, key,
// iv, 100 };
decrypt << in.rdbuf() << eoi;
}
}
catch (exception const &exc)
{
cerr << exc.what() << ’\n’;
}
bobcat/osymcryptstream - defines the class interface
bobcat(7), isymcryptstream(3bobcat), isymcryptstreambuf(3bobcat), osymcryptstreambuf(3bobcat)
None Reported.
Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.
This is free software, distributed under the terms of the GNU General Public License (GPL).
Frank B. Brokken (f.b.brokken@rug.nl).
| 2005-2022 | libbobcat-dev_6.02.02 |