FBB::ISymCryptStream(3) Istream performing symmetric encryption


#include <bobcat/isymcryptstream>
Linking option: -lbobcat -lcrypto


FBB::ISymCryptStream objects may be used to encrypt or decrypt information that is available on a separate std::istream.

The class ISymCryptStream is a class template, using a FBB::CryptType template non-type parameter. Objects of the class FBB::ISymCryptStream<FBB::ENCRYPT> encrypt the information they receive, objects of the class FBB::ISymCryptStream<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 in combination with EncryptBuf objects. To select a particular encryption method an identifier is passed to the constructor. E.g., "aes-128-cbc" indicating the AES (Rijndael) method, using 128 bit sized keys and blocks using `cbc' mode (see below for an explanation).

Refer to the isymcryptstreambuf(3bobcat) man-page for a descryption of available encryption methods.


All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.


FBB::ISymCryptStreambuf (private),


ISymCryptStream<CryptType>( std::istream &in, char const *type, std::string const &key, std::string const &iv, size_t bufSize = 100, size_t filterBufSize = 1000, ENGINE *engine = 0):
This constructor initializes a std::istream providing it with an FBB::ISymCryptStreambuf stream buffer. The ISymCryptStreambuf's constructor receives all arguments that are passed to this constructor.
- ISymCryptStream<ENCRYPT> objects perform encryption;
ISymCryptStream<DECRYPT> objects perform decryption;
- ISymCryptStream<CryptType> objects obtain the bytes to encrypt or decrypt from std::istream &in;
- The encryption method to use is specified by the type parameter. E.g., "bf-cbc" selects the Blowfish Cipher Block Chaining method;
- The symmetric key to use is specified by the key parameter;
- The initialization vector is specified by the iv parameter;
- The FBB::ISymCryptStreambuf internally used buffer will contain bufSize characters. The default value is the smallest value that is used. When a smaller bufSize value is specified, the default value is used;
- The internally used IFilterStreambuf is initialized with a buffer of size filterBufSize, using a lower bound of 100;
- The parameter ENGINE can be used to specify a hardware acceleration engine, as supported by the used encryption/decryption method. Its default argument value indicates that no hardware acceleration is available.


Since the class uses public derivation from std::istream, all members of this class can be used.


#include "../isymcryptstream"
#include <iostream>
using namespace std;
using namespace FBB;
int main()
    ISymCryptStream<ENCRYPT> encryptor(cin, "bf-cbc",
                                    "1234567890", "1234567890");
    ISymCryptStream<DECRYPT> decryptor(encryptor, "bf-cbc",
                                    "1234567890", "1234567890");
    cout << decryptor.rdbuf();


bobcat/isymcryptstream - defines the class interface


Sep/Oct 2013: due to a change in library handling by the linker (cf. http://fedoraproject.org/wiki/UnderstandingDSOLinkChange and https://wiki.debian.org/ToolChain/DSOLinking) libraries that are indirectly required are no longer automatically linked to your program. With BigInt this is libcrypto, which requires programs to link to both bobcat and crypto.


  • bobcat_4.02.00-x.dsc: detached signature;
  • bobcat_4.02.00-x.tar.gz: source archive;
  • bobcat_4.02.00-x_i386.changes: change log;
  • libbobcat1_4.02.00-x_*.deb: debian package holding the libraries;
  • libbobcat1-dev_4.02.00-x_*.deb: debian package holding the libraries, headers and manual pages;
  • http://sourceforge.net/projects/bobcat: public archive location;


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 ([email protected]).