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Obfuscating first step of encryption

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  Obfuscating first step of encryption Frederick Gotham <cauldwell.thomas@gmail.com> - 2020-03-31 11:51 -0700
    Re: Obfuscating first step of encryption Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-31 23:55 +0100
      Re: Obfuscating first step of encryption Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-04-01 05:55 +0000
    Re: Obfuscating first step of encryption James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-01 09:51 -0400
      Re: Obfuscating first step of encryption Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-04-01 20:20 +0000
        Re: Obfuscating first step of encryption James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-01 17:51 -0700
          Re: Obfuscating first step of encryption Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-04-02 06:22 +0000
            Re: Obfuscating first step of encryption James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-02 09:55 -0400
            Re: Obfuscating first step of encryption Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-04 13:14 -0700
              Re: Obfuscating first step of encryption Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-04-05 17:14 +0000

#150932 — Obfuscating first step of encryption

I have triple-posted this to sci.crypt, comp.lang.c++, comp.lang.c. (I would have taken more flack for cross-posting).

I'm currently writing a paper on a cryptographic technique I have come up with. I hope to publish before the end of April.

When encrypting/decrypting a file of size from about 500 kB to 500 GB, I shall aim for my technique to be comparatively fast to the likes of Rijndael, Twofish, Serpent.

When encrypting/decrypting a small input, e.g. from 1 byte to 1 kB, my technique will be incredibly slow, as significant computation is required to load in the key and transform the first block. (The first block gets special treatment). If you had a million small files to encrypt separately, it would take thousands of times longer than if it were one large file.

It is the time taken to load in the key and transform the first block that shall make my technique far less susceptible to brute-forcing. I hear that the Blowfish algorithm was admired for this reason because loading in the key is as expensive as encrypting 4 kB of data.

Has anyone any thoughts on deliberately obfuscating the first step of an encryption algorithm, with the consequence of severe inefficiency when encrypting small files, but with the aim of making brute-forcing extremely time-consuming?

I'm coding my technique in C++ for multi-threaded high performance on modern PC's (and supercomputers). I've got an x86-64 machine with 20 cores to test this on.

Also I'm coding my technique single-threadedly in C for minimal ROM and RAM usage on microcontrollers. I won't be able to get it small enough for 8-bit microcontrollers, but a 32-Bit PIC should be more than powerful enough.

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#150937

Frederick Gotham <cauldwell.thomas@gmail.com> writes:

> I have triple-posted this to sci.crypt, comp.lang.c++, comp.lang.c. (I
> would have taken more flack for cross-posting).

Not from me.  Your post is topical in only one of the three groups
(mentioning the programming language does not make this post about C or
C++) and cross-posting would mean I'd see it only once.  Oh well, each
to their own.  There are bigger problems...

<cut>
-- 
Ben.

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#150939

On Tue, 2020-03-31, Ben Bacarisse wrote:
> Frederick Gotham <cauldwell.thomas@gmail.com> writes:
>
>> I have triple-posted this to sci.crypt, comp.lang.c++, comp.lang.c. (I
>> would have taken more flack for cross-posting).
>
> Not from me.

Nor from me.

> Your post is topical in only one of the three groups

Yes, that's the problem.

To point out something positive: this is at least better than
/silently/ multiposting.

> Oh well, each to their own.  There are bigger problems...

Yes -- we need to settle the brace style problem once and for all!
:-)

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#150943

On 3/31/20 2:51 PM, Frederick Gotham wrote:
> I have triple-posted this to sci.crypt, comp.lang.c++, comp.lang.c. (I would have taken more flack for cross-posting).

Well, it's off-topic in both comp.lang.c and comp.lang.c++ - just
because you use a particular language to implement an algorithm doesn't
make a forum devoted to that language an appropriate place to discuss
it. Only if language-specific issues come up would it be appropriate to
discuss it here. Your question is entirely about the algorithm, not the
implementation.

You've claimed that more people complain to you about cross-posting than
about multi-posting, so I want to add myself to your statistics:
cross-posting is far better (when the subject is on-topic in all of the
groups) so that everyone interested can see responses posted in any of
the newsgroups.

I would oppose cross-posting to any newsgroup where the subject is
off-topic, such as this one - but that's because it's off-topic, not
because you're cross-posting. I'd object just as strongly to
multi-posting off-topic messages, or single-posting them.

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#150948

On Wed, 2020-04-01, James Kuyper wrote:
> On 3/31/20 2:51 PM, Frederick Gotham wrote:
>> I have triple-posted this to sci.crypt, comp.lang.c++,
>> comp.lang.c. (I would have taken more flack for cross-posting).
...
> You've claimed that more people complain to you about cross-posting than
> about multi-posting, so I want to add myself to your statistics:
> cross-posting is far better (when the subject is on-topic in all of the
> groups) so that everyone interested can see responses posted in any of
> the newsgroups.

This was discussed when he started doing it some time last year, and
one or two regulars wrote at length about why multi-posting was much
better.  (This surprised me at the time.)  Anyway, that's probably
where he got that from.

[snip stuff about offtopicness which I agree with fully]

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#150949

On Wednesday, April 1, 2020 at 4:20:27 PM UTC-4, Jorgen Grahn wrote:
> On Wed, 2020-04-01, James Kuyper wrote:
> > On 3/31/20 2:51 PM, Frederick Gotham wrote:
> >> I have triple-posted this to sci.crypt, comp.lang.c++,
> >> comp.lang.c. (I would have taken more flack for cross-posting).
> ...
> > You've claimed that more people complain to you about cross-posting than
> > about multi-posting, so I want to add myself to your statistics:
> > cross-posting is far better (when the subject is on-topic in all of the
> > groups) so that everyone interested can see responses posted in any of
> > the newsgroups.
> 
> This was discussed when he started doing it some time last year, and
> one or two regulars wrote at length about why multi-posting was much
> better.  (This surprised me at the time.)  Anyway, that's probably
> where he got that from.

According to Google Groups, he started posting with his current e-mail
address sometime in November last year. On 2020-12-01, he said "I have
found that people who are adverse to cross-posting greatly outnumber
those who are adverse to multi-posting." That was before he'd had any
significant conversation about that subject in this newsgroup using that
e-mail address. The last time prior to that when anybody used the name
"Frederick Gotham" to post a message in comp.lang.c was in 2006, using a
different e-mail address. I don't know when he reached that conclusion,
but I don't think he reached it based upon recent experience using this
e-mail address in this newsgroup.

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#150950

On Thu, 2020-04-02, James Kuyper wrote:
> On Wednesday, April 1, 2020 at 4:20:27 PM UTC-4, Jorgen Grahn wrote:
>> On Wed, 2020-04-01, James Kuyper wrote:
>> > On 3/31/20 2:51 PM, Frederick Gotham wrote:
>> >> I have triple-posted this to sci.crypt, comp.lang.c++,
>> >> comp.lang.c. (I would have taken more flack for cross-posting).
>> ...
>> > You've claimed that more people complain to you about cross-posting than
>> > about multi-posting, so I want to add myself to your statistics:
>> > cross-posting is far better (when the subject is on-topic in all of the
>> > groups) so that everyone interested can see responses posted in any of
>> > the newsgroups.
>> 
>> This was discussed when he started doing it some time last year, and
>> one or two regulars wrote at length about why multi-posting was much
>> better.  (This surprised me at the time.)  Anyway, that's probably
>> where he got that from.
>
> According to Google Groups, he started posting with his current e-mail
> address sometime in November last year. On 2020-12-01, he said "I have
> found that people who are adverse to cross-posting greatly outnumber
> those who are adverse to multi-posting." That was before he'd had any
> significant conversation about that subject in this newsgroup using that
> e-mail address.

This was where I asked him to stop multi-posting, and then some people
(at least Tim R.)  disagreed.  He must have followed that second
advise immediately, then.

  Subject: Re: Discarding unneeded object files
  Date: Sun, 1 Dec 2019 09:42:15 +0100
  Message-ID: <slrnqu6v77.2ntj.grahn+nntp@frailea.sa.invalid>

Sorry for making a big deal of this; how this happened isn't really a
big deal.

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#150951

On 4/2/20 2:22 AM, Jorgen Grahn wrote:
> On Thu, 2020-04-02, James Kuyper wrote:
...
>> According to Google Groups, he started posting with his current e-mail
>> address sometime in November last year. On 2020-12-01, he said "I have
>> found that people who are adverse to cross-posting greatly outnumber
>> those who are adverse to multi-posting." That was before he'd had any
>> significant conversation about that subject in this newsgroup using that
>> e-mail address.
> 
> This was where I asked him to stop multi-posting, and then some people
> (at least Tim R.)  disagreed.  He must have followed that second
> advise immediately, then.

Actually, if his statement reflected a decision to follow Tim's advice,
it was not merely immediate, but pre-cognitive.

>   Subject: Re: Discarding unneeded object files
>   Date: Sun, 1 Dec 2019 09:42:15 +0100
>   Message-ID: <slrnqu6v77.2ntj.grahn+nntp@frailea.sa.invalid>
> 
> Sorry for making a big deal of this; how this happened isn't really a
> big deal.

I agree that it's not a big deal, and I apologize for continuing to
discuss this, but my point was that Frederick Gotham responded to your
message on 2019-12-01 at 05:10:31 -0800, and in his response he made the
statement I've quoted above. According to Google groups, at that time,
your message was the only advice he'd been given about cross-posting vs.
multi-posting in this newsgroup since he started posting with that
e-mail address, on 2019-11-04. Tim did not post his comment until
2019-12-01 at 09:39:20 -0800, so Gotham's statement could not have been
referring to Tim's message. It had to be about responses he got prior to
that time, either in some other newsgroup, or while posting here with at
different e-mail address.

All of this is based upon Google Groups archives, and so should be taken
with a grain of salt.

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#151017

Jorgen Grahn <grahn+nntp@snipabacken.se> writes:

> On Thu, 2020-04-02, James Kuyper wrote:
>
>> On Wednesday, April 1, 2020 at 4:20:27 PM UTC-4, Jorgen Grahn wrote:
>>
>>> On Wed, 2020-04-01, James Kuyper wrote:
>>>
>>>> On 3/31/20 2:51 PM, Frederick Gotham wrote:
>>>>
>>>>> I have triple-posted this to sci.crypt, comp.lang.c++,
>>>>> comp.lang.c.  (I would have taken more flack for cross-posting).
>>>
>>> ...
>>>
>>>> You've claimed that more people complain to you about cross-posting than
>>>> about multi-posting, so I want to add myself to your statistics:
>>>> cross-posting is far better (when the subject is on-topic in all of the
>>>> groups) so that everyone interested can see responses posted in any of
>>>> the newsgroups.
>>>
>>> This was discussed when he started doing it some time last year, and
>>> one or two regulars wrote at length about why multi-posting was much
>>> better.  (This surprised me at the time.)  Anyway, that's probably
>>> where he got that from.
>>
>> According to Google Groups, he started posting with his current e-mail
>> address sometime in November last year.  On 2020-12-01, he said "I have
>> found that people who are adverse to cross-posting greatly outnumber
>> those who are adverse to multi-posting."  That was before he'd had any
>> significant conversation about that subject in this newsgroup using that
>> e-mail address.
>
> This was where I asked him to stop multi-posting, and then some people
> (at least Tim R.) disagreed.

I feel a need to clarify here.  My earlier remarks (ie, from last
year) about cross-posting and multi-posting were made regarding
only the particular context of comp.lang.c and comp.lang.c++.  Also
my position is not absolute.  Based on past experience I think it
is /generally/ true (for the particular case of {clc,clc++}) that
multi-posting gives a better result than cross-posting, but that
does not necessarily hold in all cases.  I don't mean to reactivate
the discussion;  I just wanted to clarify what it was that I said.

On the other topic, AFAIK my earlier comments played no part in
the forming of Mr. Gotham's views on the subject.

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#151084

On Sat, 2020-04-04, Tim Rentsch wrote:
> Jorgen Grahn <grahn+nntp@snipabacken.se> writes:
...
>> This was where I asked him to stop multi-posting, and then some people
>> (at least Tim R.) disagreed.
>
> I feel a need to clarify here.  My earlier remarks (ie, from last
> year) about cross-posting and multi-posting were made regarding
> only the particular context of comp.lang.c and comp.lang.c++.  Also
> my position is not absolute.  Based on past experience I think it
> is /generally/ true (for the particular case of {clc,clc++}) that
> multi-posting gives a better result than cross-posting, but that
> does not necessarily hold in all cases.  I don't mean to reactivate
> the discussion;  I just wanted to clarify what it was that I said.

Yes, that's how I remember it too.

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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