Re: [GNU Crypto] Documentation

[baz]

Hi,

Thanks for the replies. The documentation that exists certainly goes some
way towards filling in the blanks from what I've gleaned from the source
code.

Actually, I know there are some gaps, but what documentation there is
excellent as it is brief and to the point. How about putting a link to it on
the home page?

Also I like the idea behind the assembly stuff, as that's exactly what I
started doing when I first downloaded the library. I think what any software
designer wants is a very easy to use layer to specify any number of
transformations and an equally easy way to turn this into a ready to use
cipher.

How about renaming 'Stage.getInstace'?  :-)

Lastly, there is nothing in the library for generating keys. Correct me if
I'm wrong but I thought that not all encryption schemes use an entirely
random sequence of bits for their keys. Don't some require a certain parity?

Many thanks once again,
barry


----- Original Message -----
From: "Raif S. Naffah" <address@hidden>
To: "Casey Marshall" <address@hidden>; "baz"
<address@hidden>
Cc: "GNU Crypto" <address@hidden>
Sent: Sunday, May 25, 2003 2:29 AM
Subject: Re: [GNU Crypto] Documentation


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On Sat, 24 May 2003 01:41 pm, Casey Marshall wrote:
> On Fri, May 23, 2003 at 10:27:28PM +0100, baz wrote:
> > ...
> > Can someone tell me if there exists some basic design documentation
> > for gnu-crypto?...
> >
> > Documentation is limited to the source code/javadoc and the
> > references on the home page to the details of the algorithms, but
> > nothing on the basics of going about using the library.
>
> See
> <http://metastatic.org/text/Documentation/gnu-crypto/manual.html>, or
> <http://metastatic.org/text/Documentation/gnu-crypto/manual.pdf>.
>
> This documentation is not complete, and really isn't official yet,
> but may still give some insight even as a rough draft. I haven't had
> time to work on it lately, but may try to get working on it again
> soon.
>
> The basic usage of GNU Crypto objects is typically:
>
>    1. Create an object with a factory method.
>    2. Initialize the object with an attributes Map.
>    3. Use the object.
>    4. Reset the object and go to step 2.
>
> Also note that many algorithms are low-level, e.g. with block ciphers
> it is up to you to break the input data into block-sized chunks
> before you feed them to the {en,de}cryptBlock methods...

it is worth adding at this point, that with the recent additions to the
library of the gnu.crypto.assembly packages, you can do things similar
to what the JCE allows you to by using an "cipher/mod/padding" name
construction, and more.  have a look at the two test (example) classes:

gnu.testlet.gnu.crypto.assembly.TestOfAssembly, and
gnu.testlet.gnu.crypto.assembly.TestOfCascade.

the first one demonstrates how one can build a 3-des cipher from 3
separate des ciphers, while the second demonstrates how to build a
construction that (a) encrypts/decrypts, (b) in a given mode, (c) with
padding/unpadding, and (d) with compression/decompression.


cheers;
rsn
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