NAME¶

FBB::ISymCryptStream - Istream performing symmetric encryption

SYNOPSIS¶

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

DESCRIPTION¶

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.

NAMESPACE¶

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

INHERITS FROM¶

FBB::ISymCryptStreambuf (private), std::istream

CONSTRUCTOR¶

o

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 accelleration engine, as supported by the used encryption/decryption method. Its default argument value indicates that no hardware accelleration is available.

INHERITED MEMBERS¶

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

EXAMPLE¶

#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();
}

FILES¶

bobcat/isymcryptstream - defines the class interface

SEE ALSO¶

bobcat(7), isymcryptstreambuf(3bobcat)

BUGS¶

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.

DISTRIBUTION FILES¶

o

bobcat_3.23.01-x.dsc: detached signature;

o

bobcat_3.23.01-x.tar.gz: source archive;

o

bobcat_3.23.01-x_i386.changes: change log;

o

libbobcat1_3.23.01-x_*.deb: debian package holding the libraries;

o

libbobcat1-dev_3.23.01-x_*.deb: debian package holding the libraries, headers and manual pages;

o

http://sourceforge.net/projects/bobcat: public archive location;

BOBCAT¶

Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.

COPYRIGHT¶

This is free software, distributed under the terms of the GNU General Public License (GPL).

AUTHOR¶

Frank B. Brokken ( f.b.brokken@rug.nl).