I dug up my old impl of scos2. Does this work for you?

scos2 247 742

*,B|A D@[>+i p"= ;_{ )3xy $yx5 ojts wihkb#

KWNYTZ JYFQV,H.Nw

rXZ

On 7/25/2024 3:17 PM, Chris M. Thomasson wrote:
> I dug up my old impl of scos2. Does this work for you?
>
> scos2 247 742
>
> *,B|A D@[>+i p"= ;_{ )3xy $yx5 ojts wihkb#
>
> KWNYTZ JYFQV,H.Nw
>
> rXZ
>
>

I finally found the original SCOS2 code! Here it is:

scos2 712 901

v^qC{3J= MeCyaDVf5
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3=yK;"R@ UmK-iK&AKk
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Chris M. Thomasson <chris.m.thomasson.1@gmail.com> wrote:
> I dug up my old impl of scos2. Does this work for you?
>
> scos2 247 742
>
> *,B|A D@[>+i p"= ;_{ )3xy $yx5 ojts wihkb#
>
> KWNYTZ JYFQV,H.Nw
>
> rXZ

scos2 65 33

0ZGS XB sJ@ lH ~i<8/

On 7/25/2024 8:54 PM, Rich wrote:
> scos2 65 33
>
> 0ZGS XB sJ@ lH ~i<8/

For some reason I am getting a plaintext of:

~U9o My 8/g v[ Ym9\;

using my impl and Rich's original scos2 impl.

Here is the ciphertext for using Rich's original SCOS2 with a key of 3 7
________
Hello World
________

Ko29_ 8/CDC

Can you decrypt it? Thanks.

On 26/07/2024 06:15, Chris M. Thomasson wrote:
> On 7/25/2024 8:54 PM, Rich wrote:
>> scos2 65 33
>>
>> 0ZGS XB sJ@ lH ~i<8/
>
> For some reason I am getting a plaintext of:
>
> ~U9o My 8/g v[ Ym9\;
>
> using my impl and Rich's original scos2 impl.

The key is wrong, try:

28 60
0ZGS XB sJ@ lH ~i<8/

Chris M. Thomasson <chris.m.thomasson.1@gmail.com> wrote:
> On 7/25/2024 8:54 PM, Rich wrote:
>> scos2 65 33
>>
>> 0ZGS XB sJ@ lH ~i<8/
>
> For some reason I am getting a plaintext of:
>
> ~U9o My 8/g v[ Ym9\;

I do too, when I try.

Give this a try instead:

,j@& t, Mr, R1 Ga3\,

> using my impl and Rich's original scos2 impl.
>
> Here is the ciphertext for using Rich's original SCOS2 with a key of 3 7
> ________
> Hello World
> ________
>
> Ko29_ 8/CDC
>
>
> Can you decrypt it? Thanks.

Yes.

Chris M. Thomasson in sci.crypt:

[...]

>I finally found the original SCOS2 code! Here it is:
>
>scos2 712 901
[...]

scos2 712 901
(" 1O: lN)2S~ ^Z? -YD) sG :rL "SB(} VE5d P=

<wT;2Z,8fC^lI-rO]xU:3a<9gD&mJ+sP#yV/4b\!hE*nK=tQ~zW?5c|"i
5mL^qT(]Y,sQA$' aZlgK.
z
(vZ{
\
S|%bD+en]yF)2Zq
~IDxa> +cL#8 P'pN ;wn~yn, ^fW)uGo0v
S"S>TYK'rS [xJ@ 6P["VHU>HC
^_[lXB4fB %l/9l >-h X@sa{8 b< ^m?*tPE
* w ]zL} v S\zlP)tPf j G_oaE7iES?FA_3
T

yI.7b. _+
l X*nK=tQ~zW?5c|"iF(oL{uR'0X.6dA$jG)pM}vS@1Y>7eB%kH_qN[wT;2

D5i D4iL^d D%z D 7T}I{v E)h <)s Q$vWDHM >y

rW~wW/4eE8lHql]uU@35Y"!cBjo=rqS0s/41b\hgB)l}tPL=YU~6b\7eAllL=tU2

:\=tM#<!hsa.$eESbG)hJ^BG@z(~Li@7;>=0O@AHjY~FkjV5PBrT7}Bz4%t;jN>be!q|

~%1J{1
--
╮ ╭─╮ ╭────╮ ╭────╮ ..41..╭────────╮ ╭──────────
╰──╯ ╰─╮ ╭────╯ ╭─╯ ╭─╯ ╭─╯ │ ╭────╯ │ ..67..
╰─╮ ╭──╮ ╰───╮ ╰─╮ │ ╭─╯ ╭───────╮ │ ╰─╮ ╭─╮ ╭─╯ ..67..
╰─╯ ╰──────╯ ╰─╯ ╰───╯ ╰─╯ ╰──╯ ╰─╯ ..67..

Marcel Logen in sci.crypt:

>Chris M. Thomasson in sci.crypt:

>[...]
>
>>I finally found the original SCOS2 code! Here it is:
>>
>>scos2 712 901
>[...]
>
>scos2 712 901

Sorry, this should read:

/----------------------
(" 1O: lN)2S~ ^Z? -YD) sG :rL "SB(} VE5d P=

<wT;2Z,8fC^lI-rO]xU:3a<9gD&mJ+sP#yV/4b\!hE*nK=tQ~zW?5c|"i
5mL^qT(]Y,sQA$' aZlgK.
z
(vZ{
\
S|%bD+en]yF)2Zq
~IDxa> +cL#8 P'pN ;wn~yn, ^fW)uGo0v
S"S>TYK'rS [xJ@ 6P["VHU>HC
^_[lXB4fB %l/9l >-h X@sa{8 b< ^m?*tPE
* w ]zL} v S\zlP)tPf j G_oaE7iES?FA_3
T

yI.7b. _+
l X*nK=tQ~zW?5c|"iF(oL{uR'0X.6dA$jG)pM}vS@1Y>7eB%kH_qN[wT;2

D5i D4iL^d D%z D 7T}I{v E)h <)s Q$vWDHM >y

rW~wW/4eE8lHql]uU@35Y"!cBjo=rqS0s/41b\hgB)l}tPL=YU~6b\7eAllL=tU2

:\=tM#<!hsa.$eESbG)hJ^BG@z(~Li@7;>=0O@AHjY~FkjV5PBrT7}Bz4%t;jN>be!q|
\----------------------

Marcel (Lines: 47)
--
╭────────╮ ╭─╮ ╭─╮ ╭─────╮ ╭─╮..49..╭──────╮ ╭──╮
...3..╭─╮ ╰─────╮ ╰──╯ ╰───╯ │ ╰───╮ ╰──╯ ╰─╮ ╭─╯ ╭──╮ │ │ │
╭───╮ │ │ ╭──────╯ ..28..╰───╮ ╰─╮ ╭───╯ ╰───╯ │ ╰─╯ │ ╭─
╭─╯ ╰─╯ ╰─╯ ╰────╯ ╰─────────────╯..61..╰───╯

Marcel Logen in sci.crypt:

>Marcel Logen in sci.crypt:

>>scos2 712 901
>
>Sorry, this should read:

/----------------------
(" 1O: lN)2S~ ^Z? -YD) sG :rL "SB(} VE5d P=

<wT;2Z,8fC^lI-rO]xU:3a<9gD&mJ+sP#yV/4b\!hE*nK=tQ~zW?5c|"i
5mL^qT(]Y,sQA$' aZlgK.
z
(vZ{
\
S|%bD+en]yF)2Zq
~IDxa> +cL#8 P'pN ;wn~yn, ^fW)uGo0v
S"S>TYK'rS [xJ@ 6P["VHU>HC
^_[lXB4fB %l/9l >-h X@sa{8 b< ^m?*tPE
* w ]zL} v S\zlP)tPf j G_oaE7iES?FA_3
T

yI.7b. _+
l X*nK=tQ~zW?5c|"iF(oL{uR'0X.6dA$jG)pM}vS@1Y>7eB%kH_qN[wT;2

D5i D4iL^d D%z D 7T}I{v E)h <)s Q$vWDHM >y

rW~wW/4eE8lHql]uU@35Y"!cBjo=rqS0s/41b\hgB)l}tPL=YU~6b\7eAllL=tU2

:\=tM#<!hsa.$eESbG)hJ^BG@z(~Li@7;>=0O@AHjY~FkjV5PBrT7}Bz4%t;jN>be!q|
>\----------------------

Please note the indentation.

Marcel (Lines: 42)
--
╭───╮ ╭───╮ ╭────╮ ..67..
╰─╮ ╰─╮ ╭─╯ ╰──╮ ╭─╮ ╭─╮ ╭────╯ ╰─╮ ..67..
╮ ╰─╮ │ ╭─╮ ╭──╮ ╭───╮ ╭──╯ ╭─────╯ │ │ │ ╰─╯ ..57..╰────╮
╰────╯ ╰─╯ ╰───╯ ╰─╯ ╰─╯ ╰────────╯ ╰──╯ ..62..╰────

Marcel Logen in sci.crypt:

>Marcel Logen in sci.crypt:
>>Marcel Logen in sci.crypt:

>>>scos2 712 901
>>
>>Sorry, this should read:

/----------------------
(" 1O: lN)2S~ ^Z? -YD) sG :rL "SB(} VE5d P=

<wT;2Z,8fC^lI-rO]xU:3a<9gD&mJ+sP#yV/4b\!hE*nK=tQ~zW?5c|"i
5mL^qT(]Y,sQA$' aZlgK.
z
(vZ{
\
S|%bD+en]yF)2Zq
~IDxa> +cL#8 P'pN ;wn~yn, ^fW)uGo0v
S"S>TYK'rS [xJ@ 6P["VHU>HC
^_[lXB4fB %l/9l >-h X@sa{8 b< ^m?*tPE
* w ]zL} v S\zlP)tPf j G_oaE7iES?FA_3
T

yI.7b. _+
l X*nK=tQ~zW?5c|"iF(oL{uR'0X.6dA$jG)pM}vS@1Y>7eB%kH_qN[wT;2

D5i D4iL^d D%z D 7T}I{v E)h <)s Q$vWDHM >y

rW~wW/4eE8lHql]uU@35Y"!cBjo=rqS0s/41b\hgB)l}tPL=YU~6b\7eAllL=tU2

:\=tM#<!hsa.$eESbG)hJ^BG@z(~Li@7;>=0O@AHjY~FkjV5PBrT7}Bz4%t;jN>be!q|
\----------------------

>Please note the indentation.

Oh, it's too hard for me! ;-)

Marcel (Lines: 45)
--
│ ╭──╮ ╭────╮ ╭───────╮ ╭─╮ ..61..╭──╮
╰─╮ ╭─╯ ╰─╯ ╰─╮ ╰────╮ ╰───╯ ╰──╮ ..57..╭───╯ ╰──
│ ╭───╮ ╭───╯ ╭──────╯ ╭─╮ ╰───╮ ╭────╯ ╭─╮ │ ..67..
╰─────╯ ╰──╯ ╰─────────╯ ╰───────╯ ╰──────╯ ╰───╯ ..67..

On 7/26/2024 6:55 AM, Rich wrote:
> Chris M. Thomasson <chris.m.thomasson.1@gmail.com> wrote:
>> On 7/25/2024 8:54 PM, Rich wrote:
>>> scos2 65 33
>>>
>>> 0ZGS XB sJ@ lH ~i<8/
>>
>> For some reason I am getting a plaintext of:
>>
>> ~U9o My 8/g v[ Ym9\;
>
> I do too, when I try.

Ahhh good. I thought it might be an issue in my crude impl, then when
Richards original SCOS2 gave the same output, I was like humm... Key
issues? Pondering... ;^)

> Give this a try instead:
>
> ,j@& t, Mr, R1 Ga3\,

Works like a charm with 65 33. Thanks Rich.

>> using my impl and Rich's original scos2 impl.
>>
>> Here is the ciphertext for using Rich's original SCOS2 with a key of 3 7
>> ________
>> Hello World
>> ________
>>
>> Ko29_ 8/CDC
>>
>>
>> Can you decrypt it? Thanks.
>
> Yes.

Perfect.

On 7/26/2024 2:32 AM, Richard Harnden wrote:
> On 26/07/2024 06:15, Chris M. Thomasson wrote:
>> On 7/25/2024 8:54 PM, Rich wrote:
>>> scos2 65 33
>>>
>>> 0ZGS XB sJ@ lH ~i<8/
>>
>> For some reason I am getting a plaintext of:
>>
>> ~U9o My 8/g v[ Ym9\;
>>
>> using my impl and Rich's original scos2 impl.
>
> The key is wrong, try:
>
> 28 60
> 0ZGS XB sJ@ lH ~i<8/

Indeed it works like a charm. It had to be a "key issue". Humm... That
would be a fun test? Try different keys and log "readable" results wrt
decrypted plaintext? ;^)

On 7/26/2024 8:36 AM, Marcel Logen wrote:
> Chris M. Thomasson in sci.crypt:
>
> [...]
>
>> I finally found the original SCOS2 code! Here it is:
>>
>> scos2 712 901
> [...]
>
> scos2 712 901
[...]

1930...9f

?

"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:

> On 7/26/2024 2:32 AM, Richard Harnden wrote:
>> On 26/07/2024 06:15, Chris M. Thomasson wrote:
>>> On 7/25/2024 8:54 PM, Rich wrote:
>>>> scos2 65 33
>>>>
>>>> 0ZGS XB sJ@ lH ~i<8/
>>>
>>> For some reason I am getting a plaintext of:
>>>
>>> ~U9o My 8/g v[ Ym9\;
>>>
>>> using my impl and Rich's original scos2 impl.
>> The key is wrong, try:
>> 28 60
>> 0ZGS XB sJ@ lH ~i<8/
>
> Indeed it works like a charm. It had to be a "key issue". Humm... That
> would be a fun test? Try different keys and log "readable" results wrt
> decrypted plaintext? ;^)

Yes. Somewhere I have a program that just tries all keys. I was going
to get it to stop when English (or C) letter frequencies were found but
it turned out simpler just to eyeball the output. As a human, you can
spot a decrypt a mile off and, if I remember correctly, SCOS has "close
decrypts" that I could spot but which would look, statistically, like
plaintext.

--
Ben.

On 27/07/2024 01:20, Ben Bacarisse wrote:
> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
>
>> On 7/26/2024 2:32 AM, Richard Harnden wrote:
>>> On 26/07/2024 06:15, Chris M. Thomasson wrote:
>>>> On 7/25/2024 8:54 PM, Rich wrote:
>>>>> scos2 65 33
>>>>>
>>>>> 0ZGS XB sJ@ lH ~i<8/
>>>>
>>>> For some reason I am getting a plaintext of:
>>>>
>>>> ~U9o My 8/g v[ Ym9\;
>>>>
>>>> using my impl and Rich's original scos2 impl.
>>> The key is wrong, try:
>>> 28 60
>>> 0ZGS XB sJ@ lH ~i<8/
>>
>> Indeed it works like a charm. It had to be a "key issue". Humm... That
>> would be a fun test? Try different keys and log "readable" results wrt
>> decrypted plaintext? ;^)
>
> Yes. Somewhere I have a program that just tries all keys. I was going
> to get it to stop when English (or C) letter frequencies were found but
> it turned out simpler just to eyeball the output. As a human, you can
> spot a decrypt a mile off and, if I remember correctly, SCOS has "close
> decrypts" that I could spot but which would look, statistically, like
> plaintext.
>

I have one that tries to find consistent incr's in 3-letter word-blocks.
Hopefully the correct base and incr bubble to the top.

It's better with longer texts, but ...

$ cat test.scos
0ZGS XB sJ@ lH ~i<8/

$ ./decode_scos test.scos | ./scos
../decode_scos: Not sure, but ...
> -28 -60
> Yes, it can be read.

> -71 -60
> =~Bu :C ]}, [~ A~}#s

Chris M. Thomasson in sci.crypt:

>On 7/26/2024 8:36 AM, Marcel Logen wrote:
>>Chris M. Thomasson in sci.crypt:

>>>I finally found the original SCOS2 code! Here it is:
[...]

>1930...9f
>
>?

That's OK.

But note: The indentation in the whole code is done by
two SPACEs per step. Exception: in the last "fprintf"
command.

Marcel (Lines: 24)
--
╭────╮ ╭────╮ ╭──╮ ╭───────╮ ╭─╮ ..67..
╭───╯ ╭─╯ ╰─╮ │ ╭─╯ ╰─╮ ╭─╮ ╭─╮ ╰─────╮ ╰─╯ ╰─╮ ╭───╮
│ ╰─╮ ╭─╯ ╰─╯ ╭─╯ │ ╰─╮ ╭─╯ ╰────╮ │ ..55..╰─╯ │ ╭─╮
╭──╯ ╰────╯ ╰───╯ ╰─╯ ╰───╯ ..61..╰─╯ ╰─

Marcel Logen in sci.crypt:

>Chris M. Thomasson in sci.crypt:

[SHA256 of SCOS2 code]
>>1930...9f
>>
>>?
>
>That's OK.
>
>But note: The indentation in the whole code is done by
>two SPACEs per step. Exception: in the last "fprintf"
>command.

The file size of Richard Heathfield's code is
1753 Bytes, BTW. (After changing the last fprintf
command.)

Original reference implementation:
<http://al.howardknight.net/?ID=166748721500>
(without change in the last fprintf)

Change:
<http://al.howardknight.net/?ID=166786341400>

Marcel (Lines: 32)
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On 7/27/2024 12:20 AM, Richard Harnden wrote:
> On 27/07/2024 01:20, Ben Bacarisse wrote:
>> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
>>
>>> On 7/26/2024 2:32 AM, Richard Harnden wrote:
>>>> On 26/07/2024 06:15, Chris M. Thomasson wrote:
>>>>> On 7/25/2024 8:54 PM, Rich wrote:
>>>>>> scos2 65 33
>>>>>>
>>>>>> 0ZGS XB sJ@ lH ~i<8/
>>>>>
>>>>> For some reason I am getting a plaintext of:
>>>>>
>>>>> ~U9o My 8/g v[ Ym9\;
>>>>>
>>>>> using my impl and Rich's original scos2 impl.
>>>> The key is wrong, try:
>>>> 28 60
>>>> 0ZGS XB sJ@ lH ~i<8/
>>>
>>> Indeed it works like a charm. It had to be a "key issue". Humm... That
>>> would be a fun test? Try different keys and log "readable" results wrt
>>> decrypted plaintext? ;^)
>>
>> Yes.  Somewhere I have a program that just tries all keys.  I was going
>> to get it to stop when English (or C) letter frequencies were found but
>> it turned out simpler just to eyeball the output.  As a human, you can
>> spot a decrypt a mile off and, if I remember correctly, SCOS has "close
>> decrypts" that I could spot but which would look, statistically, like
>> plaintext.
>>
>
> I have one that tries to find consistent incr's in 3-letter word-blocks.
>  Hopefully the correct base and incr bubble to the top.
>
> It's better with longer texts, but ...
>
> $ cat test.scos
> 0ZGS XB sJ@ lH ~i<8/
>
> $ ./decode_scos test.scos | ./scos
> ./decode_scos: Not sure, but ...
> > -28 -60
> > Yes, it can be read.
>
> > -71 -60
> > =~Bu :C ]}, [~ A~}#s
>
>

The key space is not that massive, so it can be brute forced for sure.
However, its interesting wrt the plaintext. What if the plaintext is
generated from a random source?

On 7/30/2024 9:08 PM, Chris M. Thomasson wrote:
> On 7/27/2024 12:20 AM, Richard Harnden wrote:
>> On 27/07/2024 01:20, Ben Bacarisse wrote:
>>> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
[...]
> The key space is not that massive, so it can be brute forced for sure.
> However, its interesting wrt the plaintext. What if the plaintext is
> generated from a random source?

Afaict, if the plaintext is random, then its going to be hard to
identify it as a legit plaintext?

On 31/07/2024 05:09, Chris M. Thomasson wrote:
> On 7/30/2024 9:08 PM, Chris M. Thomasson wrote:
>> On 7/27/2024 12:20 AM, Richard Harnden wrote:
>>> On 27/07/2024 01:20, Ben Bacarisse wrote:
>>>> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
> [...]
>> The key space is not that massive, so it can be brute forced for sure.
>> However, its interesting wrt the plaintext. What if the plaintext is
>> generated from a random source?
>
> Afaict, if the plaintext is random, then its going to be hard to
> identify it as a legit plaintext?

If the plain text is random, then you'd never know if you got the
correct decrypt anyway.

It only works for English (or C) text. It seems to work okay for French
and "lorem ipsum". It doesn't like German.

It's doubtless slower cpu-timewise that brute forcing. It saves on
eyeball-time.

On 7/31/2024 3:24 AM, Richard Harnden wrote:
> On 31/07/2024 05:09, Chris M. Thomasson wrote:
>> On 7/30/2024 9:08 PM, Chris M. Thomasson wrote:
>>> On 7/27/2024 12:20 AM, Richard Harnden wrote:
>>>> On 27/07/2024 01:20, Ben Bacarisse wrote:
>>>>> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
>> [...]
>>> The key space is not that massive, so it can be brute forced for
>>> sure. However, its interesting wrt the plaintext. What if the
>>> plaintext is generated from a random source?
>>
>> Afaict, if the plaintext is random, then its going to be hard to
>> identify it as a legit plaintext?
>
> If the plain text is random, then you'd never know if you got the
> correct decrypt anyway.

Bob would know the correct decrypt because he has the same secret key as
Alice? So, for some reason Alice wants to send some random data to Bob,
but encrypts it using SCOS2... Bob knows how to decrypt it via the
secret key... Eve might not be able to get at the data even with brute
force? Is this fair enough or moronic? ;^o

>
> It only works for English (or C) text.  It seems to work okay for French
> and "lorem ipsum". It doesn't like German.
>
> It's doubtless slower cpu-timewise that brute forcing. It saves on
> eyeball-time.