Libcrypt examples?

Ronald F. Guilmette rfg at
Wed Oct 15 23:45:35 CEST 2014

In message <543E3C8E.3030200 at>, 
Peter Lebbing <peter at> wrote:

>On 13/10/14 21:14, Ronald F. Guilmette wrote:
>> Mostly I just need
>> something that will be simple for me to implement in my program,
>> even though I am by no means knowledgable about cryptography
>> generally.  (Most of what little I do know has been garnered from
>> with Wikipedia.)
>>From the release announcements of Libgcrypt:
>> Thorough understanding of applied cryptography is required for proper
>> use Libgcrypt.
>So you're using the wrong tool for the job. Have you thought about using
>off-the-shelf full disk encryption,

I'm sorry.  It appears that I did not explain my requirements sufficiently
well for you to be able to immediately grasp that what you just proposed
is absolutely not a viable solution in the context of my application.

Let me try again.

I have a program.  It's written in C.  I intend to distribute it, in
binary form only, to other sites.  I do not and will not control how
any fo the local disks are configured at those other sites.

I think that you are making this far more complex than it has to be.
I stated what I needed to do, and it is quite simple.  The program
must write some small bits of data to a local disk. Ideally, these
small hunks of data should not be _easily_ decypherable.  The program
will later read the data back in, decypher it, then use it.

There *are* simply solutions to this rather trivial and common problem.
If worse comes to worse, I will cook up something rather rudimentary
myself.  But I would prefer to use something stronger.  I had hoped to
get some help with this rather simple task here, but obviously I hoped
in vain.

I should say that it seems to me rather entirely bizzare, preplexing,
and downright silly that *somebody* went to the trouble to write a
detailed, 134 page (PDF) manual for the library, and yet prospective
users of the library, such as myself, cannot find even a single modest,
real-world example of how to use the bloody thing.

If there exists a universe in which that makes sense, I'm obviously
not in it.

>Cryptography is very hard to get right. You shouldn't be designing your
>own stuff based on such a low-level library as Libgcrypt; you need a
>higher level thing where all the important bits have already been done
>for you.
>That previous paragraph is very important, the most important one of
>this mail by a long shot.

OK.  Swell.  Ignoring, for the moment, the personal condescension
implicit in your comments, and accepting your premise that I should
be using some ``higher level'' library, the question remains:  Which

I understand that you may have been attempting to be helpful, and for
that I am grateful.  However you've utterly failed to provide me with
any useful or actionable information.

P.S.  I'm still looking for the "examples at the end of the manual"
which were explicitly promised in Section 1.1 ("Getting Started")
of the Libcrypt manual.

Was that promise just inserted into the manual as some sort of cruel
joke, you know, to get naive people like me to waste a lot of time
looking for examples that aren't even actually in there?

If so, then it is working perfectly.

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