oracular (3) isymcryptstreambuf.3bobcat.gz

Provided by: libbobcat-dev_6.06.01-1_amd64 bug

NAME
       FBB::ISymCryptStreambuf - Streambuf performing symmetric en/decryption


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


DESCRIPTION
       FBB::ISymCryptStreambuf  objects  can  be  used  as  std::streambuf objects of std::istream objected, and
       encrypt or decrypt information that is made available via separate std::istream streams.

       The class ISymCryptStreambuf is a class template, using a  FBB::CryptType  template  non-type  parameter.
       Objects  of the class FBB::ISymCryptStreambuf<FBB::ENCRYPT> encrypt the information they receive, objects
       of the class FBB::ISymCryptStreambuf<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 an overview of the currently supported cipher algorithms issue  the
       command

           openssl list -cipher-algorithms

       ISymCryptStreambuf  objects  read  the  information to en/decrypt from std::istream objects, which are at
       construction-time specified as istream references or by  filename.  The  characters  that  are  thereupon
       extracted  or  read  from  ISymCryptStream  objects are en/decrypted, and could, e.g., be written to some
       output stream.


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


INHERITS FROM
       FBB::ISymCryptBase (public)

       The  class FBB::ISymCryptBase is an `internal use only’ class, derived from std::streambuf, and therefore
       ISymCryptStreambuf is a std::streambuf class.


CONSTRUCTORS
       o      ISymCryptStreambuf<CryptType>(std::istream &inStream, std::string const  &cipherName,  std::string
              const &key, std::string const &iv, size_t inBufSize = 100):
              This constructor defines a std::streambuf object encrypting or decrypting the characters which are
              read from inStream.

              - ISymCryptStreambuf<FBB::ENCRYPT> objects perform encryption;
              ISymCryptStreambuf<FBB::DECRYPT> objects perform decryption;

              - ISymCryptStreambuf<CryptType>  objects  receive  the  characters  to  encrypt  or  decrypt  from
              std::istream &in;
              - The encryption method to use is specified by the cipherName parameter. E.g., "AES-256-GCM";
              - The symmetric key to use is specified by the key parameter;
              - The initialization vector is specified by the iv parameter;
              -  The  FBB::ISymCryptStreambufbuf  internally  used  buffer  will  hold inBufSize characters. The
              default value is the smallest value that is used. When specifying a smaller bufSize value than the
              default value then the default value is used;

       o      ISymCryptStreambuf<CryptType>(std::string  const  &inStreamName,  std::string  const  &cipherName,
              std::string const &key, std::string const &iv, size_t inBufSize = 100):
              Same constructor as the previous one, but this constructor’s first parameter specifies the name of
              the file containing the characters to encrypt or decrypt.

       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,


INHERITED MEMBERS
       Since the class is publicly derived from std::istreambuf, all std::streambuf members can can be used.


MEMBER FUNCTIONS
       o      static std::string errorMsg():
              If an openssl function fails an exception is thrown mentioning the name of the  failing  function.
              In  those cases the function errorMsg can be called returning a std::string containing the openssl
              error  code  (returned  by  ERR_get_error)   and   its   textual   representation   (returned   by
              ERR_error_string).  If the reported error code is zero, then in fact no error has occurred and the
              exception was spuriously reported;

       o      static size_t keyLength(std::string const &cipherName):
              returns the minimum key length required for cipher cipherName;

       o      static size_t ivLength(std::sting const &cipherName):
              returns the minimum length of the initialization vector that is required for cipher cipherName.

       The latter two functions throw exceptions if cipherName does not contain the name of a  supported  cipher
       algorithm.


EXAMPLE
       See  the  example  in  the  isymcryptstream(3bobcat)  man-page. Instead of defining an ISymCryptStream an
       ISymCryptStreamBuf can be defined, passing its address to a std::istream which can then be  used  as  the
       ISymCryptStream used in the example.


FILES
       bobcat/isymcryptstream - defines the class interface


SEE ALSO
       bobcat(7), isymcryptstream(3bobcat), osymcryptstream(3bobcat), osymcryptstreambuf(3bobcat)


BUGS
       None Reported.


BOBCAT PROJECT FILES
       o      https://fbb-git.gitlab.io/bobcat/: gitlab project page;

       o      bobcat_6.06.01-x.dsc: detached signature;

       o      bobcat_6.06.01-x.tar.gz: source archive;

       o      bobcat_6.06.01-x_i386.changes: change log;

       o      libbobcat1_6.06.01-x_*.deb: debian package containing the libraries;

       o      libbobcat1-dev_6.06.01-x_*.deb: debian package containing the libraries, headers and manual pages;


BOBCAT
       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).


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