.TH "FBB::ISymCryptStream" "3bobcat" "2005\-2016" "libbobcat\-dev_4\&.04\&.00\-x\&.tar\&.gz" "Symmetric en\- and decryption"

.PP 
.SH "NAME"
FBB::ISymCryptStream \- Istream performing symmetric encryption
.PP 
.SH "SYNOPSIS"
\fB#include <bobcat/isymcryptstream>\fP
.br 
Linking option: \fI\-lbobcat \-lcrypto\fP 
.PP 
.SH "DESCRIPTION"
\fBFBB::ISymCryptStream\fP objects may be used to encrypt or decrypt
information that is available on a separate \fIstd::istream\fP\&.
.PP 
The \fIclass ISymCryptStream\fP is a class template, using a
\fIFBB::CryptType\fP template non\-type parameter\&. Objects of the class 
\fIFBB::ISymCryptStream<FBB::ENCRYPT>\fP encrypt the information they receive,
objects of the class \fIFBB::ISymCryptStream<FBB::DECRYPT>\fP decrypt the
information they receive\&.
.PP 
All symmetric encryption methods defined by the OpenSSL library that can
be selected by name may be used in combination with \fIEncryptBuf\fP objects\&. To
select a particular encryption method an identifier is passed to the
constructor\&. E\&.g\&., \fI\(dq\&aes\-128\-cbc\(dq\&\fP indicating the AES (Rijndael) method,
using 128 bit sized keys and blocks using `cbc\(cq\& mode (see below for an
explanation)\&.
.PP 
Refer to the \fBisymcryptstreambuf\fP(3bobcat) man\-page for a description of
available encryption methods\&.
.PP 
.SH "NAMESPACE"
\fBFBB\fP
.br 
All constructors, members, operators and manipulators, mentioned in this
man\-page, are defined in the namespace \fBFBB\fP\&.
.PP 
.SH "INHERITS FROM"
\fBFBB::ISymCryptStreambuf\fP (private), 
.br 
\fBstd::istream\fP 
.PP 
.SH "CONSTRUCTOR"
.IP o 
\fBISymCryptStream<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)\fP:
.br 
This constructor initializes a \fIstd::istream\fP providing it with an
\fIFBB::ISymCryptStreambuf\fP stream buffer\&. The \fIISymCryptStreambuf\fP\(cq\&s
constructor receives all arguments that are passed to this constructor\&.
.IP 
\- \fIISymCryptStream<ENCRYPT>\fP objects perform encryption;
.br 
\fIISymCryptStream<DECRYPT>\fP objects perform decryption;
.br 
\- \fIISymCryptStream<CryptType>\fP objects obtain the bytes to encrypt
or decrypt from \fIstd::istream &in\fP;
.br 
\- The encryption method to use is specified by the \fItype\fP
parameter\&. E\&.g\&., \fI\(dq\&bf\-cbc\(dq\&\fP selects the Blowfish Cipher Block Chaining
method;
.br 
\- The symmetric key to use is specified by the \fIkey\fP parameter;
.br 
\- The initialization vector is specified by the \fIiv\fP parameter;
.br 
\- The \fIFBB::ISymCryptStreambuf\fP internally used buffer will contain
\fIbufSize\fP characters\&. The default value is the smallest value that is
used\&. When a smaller \fIbufSize\fP value is specified, the default value is
used;
.br 
\- The internally used \fIIFilterStreambuf\fP is initialized with a buffer of
size \fIfilterBufSize\fP, using a lower bound of 100;
.br 
\- The parameter \fIENGINE\fP 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\&.

.PP 
.SH "INHERITED MEMBERS"

.PP 
Since the class uses public derivation from \fBstd::istream\fP, all members
of this class can be used\&.
.PP 
.SH "EXAMPLE"
.nf 
#include \(dq\&\&.\&./isymcryptstream\(dq\&

#include <iostream>

using namespace std;
using namespace FBB;

int main()
{
    ISymCryptStream<ENCRYPT> encryptor(cin, \(dq\&bf\-cbc\(dq\&,
                                    \(dq\&1234567890\(dq\&, \(dq\&1234567890\(dq\&);

    ISymCryptStream<DECRYPT> decryptor(encryptor, \(dq\&bf\-cbc\(dq\&,
                                    \(dq\&1234567890\(dq\&, \(dq\&1234567890\(dq\&);

    cout << decryptor\&.rdbuf();
}

.fi 

.PP 
.SH "FILES"
\fIbobcat/isymcryptstream\fP \- defines the class interface
.PP 
.SH "SEE ALSO"
\fBbobcat\fP(7), \fBisymcryptstreambuf\fP(3bobcat)
.PP 
.SH "BUGS"

.PP 
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
\fBBigInt\fP this is \fIlibcrypto\fP, which requires programs to link to both
\fIbobcat\fP and \fIcrypto\fP\&.
.PP 
.SH "DISTRIBUTION FILES"
.IP o 
\fIbobcat_4\&.04\&.00\-x\&.dsc\fP: detached signature;
.IP o 
\fIbobcat_4\&.04\&.00\-x\&.tar\&.gz\fP: source archive;
.IP o 
\fIbobcat_4\&.04\&.00\-x_i386\&.changes\fP: change log;
.IP o 
\fIlibbobcat1_4\&.04\&.00\-x_*\&.deb\fP: debian package holding the
libraries;
.IP o 
\fIlibbobcat1\-dev_4\&.04\&.00\-x_*\&.deb\fP: debian package holding the
libraries, headers and manual pages;
.IP o 
\fIhttp://sourceforge\&.net/projects/bobcat\fP: public archive location;

.PP 
.SH "BOBCAT"
Bobcat is an acronym of `Brokken\(cq\&s Own Base Classes And Templates\(cq\&\&.
.PP 
.SH "COPYRIGHT"
This is free software, distributed under the terms of the 
GNU General Public License (GPL)\&.
.PP 
.SH "AUTHOR"
Frank B\&. Brokken (\fBf\&.b\&.brokken@rug\&.nl\fP)\&.
.PP