HashCryptStreams components
Documented version: 1.0.0
The initial version of this library aims at establishing a standard
infrastructure of objects and object behaviors for
Hash/HMAC functions and symmetric cryptography algorithms. Over
this base the library will grow in time with new
algorithms/functions support providing the same programming
interface for them. The applications can adopt the future versions
by simply allowing other algorithms to be initialized and taking
some care about the length of the keys for them - no code change.
The public key (asymmetric) cryptography is not so
straightforward as the symmetric algorithms, thus there is no way
to standardize a programming interface for all the asymmetric
algorithms. In this direction the library aims at supplying not
only the ready-to-use algorithms but also means to enable the
developer to build specialized implementations over the base
algorithm and even implement custom/other algorithms using the
utility objects (e.g. the BigNumber object).
Read more:
Implemented algorithms and
functions list
Usage techniques for HashObject and
Symmetric objects
About the public
key/asymmetric cryptography. How to employ it, how to obey
standards and specific kinds of usage etc.
Stream filters - what is it?
Stream filters
The Hash/HMAC and the symmetric cryptography algorithms are
available in two forms: Direct and Stream filters. The
"direct" objects (HashObject and Symmetric object) are
used directly - the application configures the object, sets
algorithm a key and passes data for processing in several possible
forms. On the other hand the stream filters are intended
for use together with other newObjects ActiveX Pack1 stream
objects such as those from Storages and Files (file, stream in an
OLE file, memory stream) or network streams (SocketStream from
NetStreams.dll). The trick is that the application can create and
initialize such a stream filter, connect it to another stream
(file, network connection etc.) and pass it to other routines that
will just read or/and write to it as if it is a stream like any
other. In the process the data will be en/de-crypted or a hash/HMAC
will be generated, but the routines that do the reading/writing do
not need to care about that.
Read about the Stream filters
concept for more details about how and when to make effective use
of them.
Licensing
The library is partially freeware. Some functions/algorithms
require a license. Thus if a license is required depends on what
algorithm you want to use and not on the object you are using. A
license will be needed if you want to initialize an
algorithm/function that needs it, for the rest the objects will
function without such.
See the algorithms and functions list for details about which
algorithms are freeware and which require a license.
The license is one and enables all the non-free
algorithms/functions.
Note that all the algorithms/functions in version 1.0.0 are
free and will remain free in all the future versions.
Distribution and requirements.
The library's DLL is HashCryptStreams.dll. It is
self-registering COM DLL and can be included with any setup
solutions that support COM DLL installation (virtually all the
installer solutions do). The DLL can be included without
any other part of AXPack1 as long as the SFStreamCrypt and SFStreamDigest
objects are not used. If you use them in your application you need
also to deploy the AXPack1 core DLL together with HashCryptStreams.
Furthermore if you are filtering other streams with these objects
(for example a SocketStream) you would need to deploy the
respective DLL as well. The RSA, BigNumber and the other
asymmetric cryptography oriented objects are self dependent and do
pose additional requirements. Still, the actual code often uses
other objects from AXPack1 for miscellaneous tasks (such as
composing strings, structuring data etc.). If you are using
AXPack1 objects extensively, but still want to remove the unneeded
DLL be careful to determine which of them are actually involved.
If not sure or you just lost the count - redistribute all the DLL
to make sure everything is in place. |
