Bletchley Boffins III - Celebration Edition - The Something Awful Forums

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Carthag Tuek: Oct 15, 2005; Tider skal komme,
tider skal henrulle,
sl�gt skal f�lge sl�gters gang

fins posted:

looks like I have at least 3 bytes of the key

# ? Sep 9, 2016 00:15

Adbot: ADBOT LOVES YOU

# ? Jun 8, 2024 15:02

burning swine: May 26, 2004

someone do a welfare check on fins, I'm worried about him

# ? Sep 9, 2016 22:59

Carthag Tuek: Oct 15, 2005; Tider skal komme,
tider skal henrulle,
sl�gt skal f�lge sl�gters gang

he stared too long into the sun

# ? Sep 10, 2016 12:30

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

I'm going to post the key on the 14th if I see no results

# ? Sep 10, 2016 17:48

NFX: Jun 2, 2008; Fun Shoe

that does not sound like responsible disclosure!

# ? Sep 10, 2016 18:27

du -hast: Mar 12, 2003; BEHEAD THOSE WHO INSULT GENTOO

This thread is absolutely and objectively bullshit.

# ? Sep 12, 2016 13:14

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

du -hast posted:

This thread is absolutely and objectively bullshit.

Don't sign

# ? Sep 12, 2016 13:22

du -hast: Mar 12, 2003; BEHEAD THOSE WHO INSULT GENTOO

Captain Foo posted:

Don't sign

Sure my posts are absolute garbage but at least I don't masquerade them like OSI

# ? Sep 12, 2016 13:47

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

du -hast posted:

Sure my posts are absolute garbage but at least I don't masquerade them like OSI

don't vent your inability to solve this

not everyone is Alan Turing

# ? Sep 12, 2016 15:49

HoboMan: Nov 4, 2010

i've published papers about this poo poo and i can't loving remember any analysis or how to even script up some poo poo to count recurring sub-strings or whatever
i'll take the blame, everyone just blame me for being dumb instead of yourself

# ? Sep 13, 2016 00:27

mod saas: May 4, 2004; Grimey Drawer

thanks hobo man jesus

# ? Sep 13, 2016 01:02

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

if i do a challenge again, should i make it less hard?

# ? Sep 13, 2016 01:54

fins: May 31, 2011; Floss Finder

OSI bean dip posted:

- every block is shifted by 1 starting at 0 until the length of the key is met at which point we reset. this means that the plaintext/cipher key value pairs do not align the same on each block but will every N blocks
- key value pairs do roll over

Well, I'm not dead/completely insane yet, but I'm close. my " 3 bytes" were from being bad at python and worse at math. I'd somehow increased the keyspace and the reduced it in the order of ~ 3 bytes equivalent. I have some sort of mathematical derivation of a part of the key, but I'm not sure what it pertains to. I'm asking for clarification on these two points,

block shift:
is it left or right, i.e.

code:

a b c d
d a b c
c d a b
b c d a

code:

a b c d
b c d a
c d a b
d a b c

and does the shifting happen pre or post ciphering?, i.e. cipher then shift , or shift then cipher. I believe it's the former.

e:

code:

[.@localhost bletchley3]$ find . | wc -l
2989

i need another contract...

fins fucked around with this message at 02:01 on Sep 13, 2016

# ? Sep 13, 2016 01:58

burning swine: May 26, 2004

OSI bean dip posted:

if i do a challenge again, should i make it less hard?

nope, just make it different

if these are reasonably challenging you can't expect us to solve every one

if they're too easy THE GANGTAG MEANS NOTHING

# ? Sep 13, 2016 02:51

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

fins posted:

Well, I'm not dead/completely insane yet, but I'm close. my " 3 bytes" were from being bad at python and worse at math. I'd somehow increased the keyspace and the reduced it in the order of ~ 3 bytes equivalent. I have some sort of mathematical derivation of a part of the key, but I'm not sure what it pertains to. I'm asking for clarification on these two points,

block shift:
is it left or right, i.e.
code:
a b c d
d a b c
c d a b
b c d a
or
code:
a b c d
b c d a
c d a b
d a b c
and does the shifting happen pre or post ciphering?, i.e. cipher then shift , or shift then cipher. I believe it's the former.

e:
code:
[.@localhost bletchley3]$ find . | wc -l
2989
i need another contract...

if would be the second shift so 00 would become 01 or A would become B. if Z then roll over to A. that is how the shift would work

and the shift happens during the cipher so not pre or post

COACHS SPORT BAR posted:

nope, just make it different

if these are reasonably challenging you can't expect us to solve every one

if they're too easy THE GANGTAG MEANS NOTHING

i'll do one again then

# ? Sep 13, 2016 03:19

burning swine: May 26, 2004

so one of the earliest things I tried was extracting the key from the end of the ciphertext, because I made the (apparently correct) assumption that the padding would be at the end, and possibly all the same char.

I wrote a quick app that would take the last N chars of the string and just start rotating alphabets and display all the possible outputs, which was < 300, so I figured if the key was something like YOSPOSBITHC I would be able to spot it

Of course I could only guess at the order of letters/Upcase letters/numbers/symbols in the target alphabet, and after trying a bunch of likely seeming combinations I didn't get anywhere. I also tried ascii but assumed that wouldn't be it.

Would that approach have born fruit if I had gotten the alphabet right?

# ? Sep 13, 2016 03:50

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

only if you tried it on the first block since it starts at 0

# ? Sep 13, 2016 03:53

fins: May 31, 2011; Floss Finder

OSI bean dip posted:

if would be the second shift so 00 would become 01 or A would become B. if Z then roll over to A. that is how the shift would work

and the shift happens during the cipher so not pre or post

i'll do one again then

I guess what I'm asking is it the text that shifts during ciphering or the key. i.e

given a plaintext of "hellohellohellohello", a block size of 5

code:

h e l l o
h e l l o
h e l l o
h e l l o

and a key of

code:

a b c d e

would the ciphertext be

code:

h.a e.b l.c l.d o.e
h.b e.c l.d l.e o.a
h.c e.d l.e l.a o.b
h.d e.e l.a l.b o.c

code:

h.a e.b l.c l.d o.e
h.e e.a l.b l.c o.d
h.d e.e l.a l.b o.c
h.c e.d l.e l.a o.b

code:

h.a e.b l.c l.d o.e
o.a h.b e.c l.d l.e
l.a o.b h.c e.d l.e
l.a l.b o.c h.d e.e

code:

h.a e.b l.c l.d l.e
e.a l.b l.c o.d h.e
l.a l.b o.c h.d e.e
l.a o.b h.c e.d l.e

e: I think the stages form the previous ones helped (both interest and fun wise), i.e. an easier first bit and a harder second bit

# ? Sep 13, 2016 04:21

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

with the letter 'a' or a:1, when the key is applied, say 'h', which is h:7, and the shift is 1, it would become 1+7+1, so j:9

A becomes J because A has a value of 1, the letter H has a value of 7, and the shift has a value of 1

this should allow you to solve it and hopefully half-asleep me wrote this well enough for you

# ? Sep 13, 2016 06:54

oh no blimp issue: Feb 23, 2011

a pregnant woman got kicked in the stomach and miscarried today in bletchley

# ? Sep 14, 2016 21:40

spankmeister: Jun 15, 2008

Awia posted:

a pregnant woman got kicked in the stomach and miscarried today in bletchley

ffuck

That's hosed up.

# ? Sep 14, 2016 21:42

spankmeister: Jun 15, 2008

btw I'm going to Bletchley at the end of october with my class. Gonna go to BP .

# ? Sep 14, 2016 21:42

oh no blimp issue: Feb 23, 2011

spankmeister posted:

ffuck

That's hosed up.

it was a racially motivated attack

spankmeister posted:

btw I'm going to Bletchley at the end of october with my class. Gonna go to BP .

dont go into the town centre, it's a bit poo poo

# ? Sep 14, 2016 21:47

spankmeister: Jun 15, 2008

Awia posted:

it was a racially motivated attack

dont go into the town centre, it's a bit poo poo

I know, I've been there before. The whole MK area is a bit poo poo tbqh.

# ? Sep 14, 2016 21:52

oh no blimp issue: Feb 23, 2011

spankmeister posted:

I know, I've been there before. The whole MK area is a bit poo poo tbqh.

take that back, mk is perfect

# ? Sep 14, 2016 21:53

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

so choice here:

do i drop the key or do i drop the plaintext from the first block?

# ? Sep 14, 2016 21:55

vodkat: Jun 30, 2012; cannot legally be sold as vodka

Awia posted:

take that back, mk is perfect

dear awia, i hope your putting your eeeeeeee� pc to good use cracking this encryption :mrgw:

vodkat fucked around with this message at 23:00 on Sep 14, 2016

# ? Sep 14, 2016 22:15

oh no blimp issue: Feb 23, 2011

vodkat posted:

dear awia, i hope your putting your eeeeeeee� pc to good use cracking this encryption

it's sitting under my TV at the moment, really bringing the whole fung shui of the room together

# ? Sep 14, 2016 23:17

burning swine: May 26, 2004

i vote drop the key

# ? Sep 15, 2016 01:49

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

smytheisadmin

# ? Sep 15, 2016 04:12

burning swine: May 26, 2004

sweet, I did have the key length right

# ? Sep 15, 2016 05:25

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

i guess no new avs for anyone this time

if anyone gets it before 23:59 PDT, i'll give an av still

next challenge however i will be a bit different as it won't involve deciphering something

# ? Sep 15, 2016 21:05

burning swine: May 26, 2004

I'm working on it presently, if I fail i'll at least post what I've tried

# ? Sep 15, 2016 21:44

Loving Africa Chaps: Dec 3, 2007; We had not left it yet, but when I would wake in the night, I would lie, listening, homesick for it already.

Can you leave the answer till after the weekend thnx plz?????

# ? Sep 15, 2016 22:32

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

Loving Africa Chaps posted:

Can you leave the answer till after the weekend thnx plz?????

sure

# ? Sep 15, 2016 22:34

burning swine: May 26, 2004

From what I've gathered in the thread so far, paintext letter = chiphertext letter + key letter + shift, where shift starts at 0 and only increments once per block. I don't know the block size yet, but I know it's at least 13, so I figured I could at least decrypt the first 13 chars and see where that gets me. Starting from the beginning, though, I'm still getting jibberish. First letter of the ciphertext is Z, first letter of the key is s, offset is known to be 0. I've again tried a few different combinations of alphabets, various permutations of:

[lowercase][uppercase][0-9][special][space]

But I can't find an alphabet where Z + s + 0 (+ the next 5 or 6 chars) comes out to anything.

At one point you indicated that 'Z' + 1 would roll over to 'A', which seems to imply that an uppercase letter would roll over to the beginning of the uppercase subset of letters, so I'm kind of thinking I've made some incorrect assumptions about how the alphabet works. For example, I would expect the first letter of cleartext to be uppercase, but there's no 70-char alphabet with a sane layout in which a 'Z' plus an 's' would come out to a capital letter

still playing with it, but lol we've got a pile of hints and the decryption key and i'm still banging my head against a wall

# ? Sep 15, 2016 23:03

Lain Iwakura: Aug 5, 2004; The body exists only to verify one's own existence.; Taco Defender

COACHS SPORT BAR posted:

From what I've gathered in the thread so far, paintext letter = chiphertext letter + key letter + shift, where shift starts at 0 and only increments once per block. I don't know the block size yet, but I know it's at least 13, so I figured I could at least decrypt the first 13 chars and see where that gets me. Starting from the beginning, though, I'm still getting jibberish. First letter of the ciphertext is Z, first letter of the key is s, offset is known to be 0. I've again tried a few different combinations of alphabets, various permutations of:

[lowercase][uppercase][0-9][special][space]

But I can't find an alphabet where Z + s + 0 (+ the next 5 or 6 chars) comes out to anything.

At one point you indicated that 'Z' + 1 would roll over to 'A', which seems to imply that an uppercase letter would roll over to the beginning of the uppercase subset of letters, so I'm kind of thinking I've made some incorrect assumptions about how the alphabet works. For example, I would expect the first letter of cleartext to be uppercase, but there's no 70-char alphabet with a sane layout in which a 'Z' plus an 's' would come out to a capital letter

still playing with it, but lol we've got a pile of hints and the decryption key and i'm still banging my head against a wall

i used Z rolling over to A as an example--it doesn't necessarily do that. however, you have it wrong for the order

[lowercase][0-9][uppercase][special characters include space and \n]

so \n would roll over to a in this case

# ? Sep 15, 2016 23:05