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Cryptography [PART I]

Name: Cryptography 2012-10-16 22:36

Cryptography

Name: Anonymous 2012-10-16 22:55

>>3 proves that VIPPER was actually right all along; FFP and the jew spammer are the same person.

Name: Anonymous 2012-10-16 22:56

Why does >>3 prove that, >>6-kun?

Name: Anonymous 2012-10-16 23:02

>>7
Although they ``both'' post within the same hours, they never post at the same time. And now that FFP found a new way to enrage neckbeards (by spitting on cryptography), the jew spammer decided to do the same. Could be just coincidence, of course.

Name: Anonymous 2012-10-16 23:04

>>8
Oh, okay.

Name: Anonymous 2012-10-16 23:05

>>8
they never post at the same time
I have yet to see two people posting at the same time in this board.

Name: Anonymous 2012-10-16 23:33

Name: Anonymous 2012-10-16 23:41

>>11

vim ~/.mozilla/firefox/profiles/.../HTTPSEverywhereRules/world4ch.xml

<ruleset name="World4ch">
  <target host="dis.4chan.org" />

  <rule from="^http://(dis\.)?4chan\.org/" to="https://dis.4chan.org/"/>
</ruleset>

Name: Anonymous 2012-10-16 23:51

>>12
vim
Strike 1.
firefox
Strike 2.
xml
Strike 3. Stopped reading.

Name: Anonymous 2012-10-17 3:22

>>10
I see several people posting concurrently on this board pretty damn often.

Name: Anonymous 2012-10-17 9:56

>>5
Interesting; have you tested your technique against steganalysis tools?

Name: Anonymous 2012-10-17 10:07

>>11
hey i posted both of those

Name: Anonymous 2012-10-17 11:31

>>15
I have not tested my anal techniques against a stegosaurus. Why have you asked?

Name: Anonymous 2012-10-18 1:09

>>5
I wonder if this would work for audio.  On a related note, I wonder how I can get some proper vessel files; I suppose I could just record myself playing the piano and save the file as uncompressed 32-bit FLAC.

Name: Anonymous 2012-10-18 2:30

>>18
If you're going to use steganography, perhaps broadcasting the format and contents of your vessel files on the Internet is not such a great idea.

Name: Anonymous 2012-10-18 11:40

>>19
uncompressed 32-bit FLAC
holy jesus

Name: Anonymous 2012-10-18 12:46

>>20
Nothing's stopping him from compressing the audio after recording

Name: Anonymous 2012-10-18 12:48

>>20
Fine, losslessly-compressed audio. Happy now, Captain Autism?

Name: Captain Autism 2012-10-18 12:56

I am quite happy without having to listen to your shit!

Name: Anonymous 2012-10-18 13:17

>>21
Lossily-compressing audio most likely destroys all steganographically-hidden data in it.

Name: Anonymous 2012-10-18 13:26

>>24
Not if you wrote it the right way.

Name: Anonymous 2012-10-18 13:31

>>24
If you're going to need that sort of requirement, it'd also be your responsibility to write a compliant encoder. Since the FLAC encoder is free, it'd be relatively trivial to do this with FLAC.

Name: Anonymous 2012-10-18 13:36

>>26
FLAC is lossless. This means that no matter what input stream you encode with it, when you decode it you get back the exact same thing bit-for-bit (they even store a MD5 checksum of the uncompressed stream).

On another note, I don't know how you're going to get enough entropy to cover 32 bits of PCM out of a regular DAC that has probably 12 or 14 bits of resolution. I would suggest sticking to 8 bits.

Name: Anonymous 2012-10-18 16:02

>>27
Cryptography thread
FLAC
...
imouttahere.png

Name: Anonymous 2012-10-18 17:47

>>28
/le backseat bop/

Name: Anonymous 2012-10-18 18:10

>>28
fuck off, retard

Name: Anonymous 2012-10-20 2:08

>>2
What do you mean?

>>1
Here's an interesting problem; is it possible to do public key steganography (i.e. with no shared secret)?

Name: >>31 2012-10-20 2:33

exploiting mistakes made by those that are ignorant to the proper use of cryptography

Name: >>2 2012-10-20 2:34

I meana respond to >>31

Name: Anonymous 2012-10-20 2:55

>>31

I want to say no. Steganography is about making information obscure. To find the information, you need to know where to look and how it is encoded. The ``where to look'' and ``how it is encoded'' form a weak private key if you will. Although this isn't a substitute for encryption, because ``where to look'' can be brute forced by performing analysis on every piece of information that could possibly contain steganography. And ``how it is encoded'' can be brute forced by trying many known encodings. If the encoded information is not encrypted, it can be reassembled.

You can use public and private key cryptography to encrypt your messages and then transmit them using steganography. Raw encrypted data is obvious to an ease dropper. But encrypted data within steganography takes more analysis to detect.

Name: Anonymous 2012-10-20 3:13

>>34
Steganography is used to hide the evidence of transfer.

For example, alternating in your mail synonyms of the same word, you can provide a binary stream.

Name: Anonymous 2012-10-20 3:17

>>34
encrypt your messages and then transmit them using steganography.
If Mossad finds that, they will rape your anus and you will tell them all your passwords.

Name: Anonymous 2012-10-20 3:35

>>35
I guess the ease of detection depends on how much information you are trying to pack. One bit or two per email would be impossible to detect. But if your needs demand more throughput, it will look more obvious.

Name: Anonymous 2012-10-20 3:39

>>37
Just send a few Bible chapters, matching you pattern.

That is how Rabbies encode "kill christian babies" message into Talmud.

Name: Anonymous 2012-10-20 3:48

>>36
And that's why you have two keys: one that decrypts to the original message, and one that decrypts to a plausible but fake one. If you use an OTP it's trivial and impossible to prove.
Two Mossad agents operating in the US in the '70s actually did exactly that.

Name: Anonymous 2012-10-20 3:48

>>36

come   and        get
me        bro      I'
m doing          it 
        now   as I  
                 type
 this   and     you'l
l     never         
   know             
                    
     what  I'm saying
               never!

Name: Anonymous 2012-10-20 3:55

>>38

But there is a problem. When you encode your information into the bible, you will modify it slightly and the differences encode your message. However, an ease dropper will recognize the writing as the bible. All they have to do is correctly guess the exact copy you used and do a diff to get an encoding of your message. The message may still be encrypted, but if this is in the right context, this is enough to provoke suspicion.

If you are going to transmit a large amount of data using stenography this way, you should use a large original data set that is not publicly available so that the ease dropper cannot get a copy of the original to compare it to.

Name: Anonymous 2012-10-20 3:58

>>41
You dont encode, you just pick matching page.

Name: Anonymous 2012-10-20 4:01

>>42

that too is an encoding. The page number is the encoded value and this value can be determined by indexing the pages of the bible and performing a look up.

As before, it isn't a big deal if the encoded values are encrypted. But if the encoding is noticeable then the stenography didn't work.

Name: Anonymous 2012-10-20 4:06

>>43
not a page number, but the content of the page (i.e. number of comas/whitespaces)

Name: Anonymous 2012-10-20 8:32

ease dropper
What.

Name: Anonymous 2012-10-20 8:43

>>45
Here's a nice Javascript quiz for you to try.
http://a4esl.org/q/j/ck/ed-punct01.html

Name: Anonymous 2012-10-20 16:27

>>34
But encrypted data within steganography takes more analysis to detect.
Well, it would be pretty silly to use steganography not in conjunction with an encryption scheme.  Now I think it should be possible to steganographically hide a public key encrypted message as long as there are no visible unencrypted headers (and that the public key structures have uniform distribution in all their bits, which I don't think holds for all ciphers although it might be possible to adapt for some).  But yeah, for decryption, one would have to try every steg encoding scheme against every private key in storage.

Name: Anonymous 2012-10-21 1:10

>>41
ease dropper
I laughed so much I almost fell off my pedal stool.

Name: Anonymous 2012-10-21 6:36

"Haruhi-chan, have you read about public key cryptography?"
"Cryptography? Uh..."
Wait a minute. What does cryptography have to deal with Nagato? I thought you were her therapist and this would be more psychobabble. Just what is going on here?
"Secret messages? Encryption, internet security, does that give you a hint?"
"I uh eh..."

Asahina-san made a hand gesture calling Haruhi's attention. "Earth to Haruhi, Earth to Haruhi, do you read me, Haruhi?"
"Eh? Oh, sorry! It's just that this government business caught me off guard..."
Asahina-sensei chuckled. "It's understandable. Kyon-kun almost threw up the first time I met him and told him about me. So, Haruhi-chan, have you thought about the answer?"
"Uh, what was the question?"
"Public key cryptography."
"Hmmm let me see... I remember. It was about prime numbers."
"That's right. If you have two prime numbers, N1, and N2, by multiplying them you obtain a bigger number. If someone, let's say, Alice, wants to send a message to Bob, the only thing Bob needs to give Alice is the multiplied number N1*N2 = M, to encrypt her message. Bob can decrypt the message because he knows what N1 and N2 are."

Wait a minute... prime numbers, multiplying, what? I'm not very good at math, someone explain this to me.
"You seem confused, Kyon-kun. But I'll let Haruhi explain to you later. Or... you could look it up in Google."
Haruhi stared at me with an annoyed look. What? I'm still studying in High school, how was I supposed to know that?
"Anyway, if Alice wanted to obtain N1 and N2 from M to decrypt a message sent to Bob, she would need to run a supercomputer for years trying to guess what N1 and N2 are. So that's the basis for public key cryptography."
Haruhi nodded quickly, while I was just following her. Asahina-sensei continued with her speech.
"Do you know what would happen if somehow, this powerful encryption could be broken with a super-incredible computer?"
"Yes..." said Haruhi, holding her chin. "It would mean... that, all the internet would..."
Asahina-sensei finished explaining. "Nothing would be secure anymore. Private conversations, financial transactions, intelligence secrets, confidential documents, nothing would be safe. Nothing. Now, you must be wondering what this has to do with Nagato-san, right?"

Name: Anonymous 2012-10-21 11:42

Haruhi-``chan''? Who the fuck would call her like that?

Name: Anonymous 2012-10-21 11:54

>>50
You've never watched 涼宮ハルヒちゃんの憂鬱?

Name: Anonymous 2012-10-21 12:28

>>51
I did, but I don't remember anyone calling her like that.

Name: Anonymous 2012-10-21 15:56

>>48
pedal stool
Have you been shitting on your bicycle again?

Name: Anonymous 2012-10-21 17:25

>>53
Everybody sing along now...
The S&M man,
The S&M man,
The S&M man because he mixes it with love,
And makes the hurtin’ feel good.
The hurtin’ feel good.

Name: Anonymous 2012-10-21 19:50

New /prog/ challenge: write a secure and undetectable public key steganography system in less than 1000 lines in your favourite language.  You are allowed to use OpenSSL.

Name: Anonymous 2012-10-21 20:06

>>55
Nice dubs NSA-kun.

Name: Anonymous 2012-10-21 20:10

>>55
I'm too dumb for that.

Name: Anonymous 2012-10-21 20:14

>>55
Forget it, it's NP-complete.

Name: Anonymous 2012-10-21 20:51

>>56
Why the hell would the NSA encourage or even suggest the creation of such software?

Name: Anonymous 2012-10-21 20:56

>>59
To see how the enemy thinks.

Name: Anonymous 2012-10-22 1:15

>>61GET!

Name: Anonymous 2012-10-22 1:55

>>60
I don't think public development of public key crypto+steganography is really in their insane mass surveillance interests.

Name: Anonymous 2012-10-22 14:11

one-time pad master race reporting in

Name: Anonymous 2012-10-22 15:48

>>63
doesn't work for public key, fagstorm

Name: Anonymous 2012-10-22 16:09

Is it true that if you extend the Enigma machine with two more rotors, it remains secure even today?

Name: Anonymous 2012-10-22 16:15

I steganographically store messages on /prog/ by selectively claiming certain strategic post numbers.

Name: Anonymous 2012-10-22 16:20

I steganographically store messages on /prog/ by inserting zero-width spaces.

Name: Anonymous 2012-10-22 19:09

I steganographically store messages on /prog/ by exploiting Unicode homoglyphs.

Name: Anonymous 2012-10-22 21:18

>>55
Does it have to be inside an image, or can it be audio or video?

Name: Anonymous 2012-10-22 21:59

I steganographically store messages on /prog/ by plunging  homosexuals.

Name: Anonymous 2012-10-22 22:26

I steganographically store messages on /prog/ by posting sequences of mutated sentences.

Name: Anonymous 2012-10-22 23:37

>>65-67,71
Does this explain the Jew spammer?

Name: Anonymous 2012-10-22 23:45

>>72
Considering the excruciatingly low signal-to-raise ratio, I'd say yes.

Name: Anonymous 2012-10-23 13:09

So, any cool free steganalysis tools or algorithm descriptions?

Name: Anonymous 2012-10-23 13:18

>>66
I get it now! Dubs are the alphabet of an encrypted message that takes months to emit.

Name: Anonymous 2012-10-23 13:28

>>74
Here's an idea: correlate (some of) the higher 7 bits against the lower one in unaltered signal, and notice the patterns that occur.

Name: VIPPER 2012-10-23 13:50

Fuck dubs. Eat shit dubs spammer.

Name: Anonymous 2012-10-23 14:06

>>75
Yes, and the message he is sending out is check my delicious doubles.

Name: Anonymous 2012-10-24 0:00

Name: Anonymous 2012-10-24 4:25

>>79
2012-10-24 00:00
Whoa, binary decuples for the date and decimal quadruples for the time.

Name: Anonymous 2012-10-24 16:17

>>77
nice dubz bro

Name: Anonymous 2012-10-27 6:40

Name: Anonymous 2012-10-27 19:12

Is it possible to use an element of randomness in cryptography?

Name: Anonymous 2012-10-27 19:20

>>83
Nothing is random, but yes.

When you generate a key of some sort, many programs tell you to do random shit and waggle your mouse around to generate entropy (and to make you look like a tit).

Name: Anonymous 2012-10-27 19:22

>>84
Everything is random

fix't, no need to thank me.

Name: Anonymous 2012-10-27 21:45

>>84
many programs tell you to do random shit and waggle your mouse around to generate entropy
Hello '90s snake oil. I'm glad we don't live in that decade anymore.

>>83
Stream ciphers are PRNGs.

Name: Anonymous 2012-10-28 0:19

>>86
How do you get entropy, then?

Name: Anonymous 2012-10-28 0:22

Name: Anonymous 2012-10-28 2:42

>>88
ANU Quantum Random Numbers Server
HAX MY ANU SERVER

My girlfriend actually came up with this one.  I guess she's read too much /prog/ over my shoulder.

Name: Anonymous 2012-10-28 2:45

>>87
I just record my girlfriend's current mood every few minutes.

Name: Anonymous 2012-10-28 3:10

>>89
disgusting normal-chan

Name: Anonymous 2012-10-28 3:44

>>91
chan
disgusting weeaboo faggo

Name: Anonymous 2012-10-28 4:21

>>91
Don't worry, we're both fairly autistic (although she's in denial).

Name: VIPPER 2012-10-28 5:27

>>93
NOT AUTISTIC ENOUGH!

GO AWAY MENTAL GOY.

Name: Anonymous 2012-10-28 5:38

>>93
/polecat kebabs/

Name: Anonymous 2012-10-28 7:26

>>94
That may surprise you, but I invented that meme.

>>95
I've been here for longer than you've been alive.

Name: Anonymous 2012-10-28 12:10

>>92
disgusting non-weeaboo faggo

>>96
that doesn't make you less of a ``faggo'' though
back to reddit with your ``girlfriend'' please

Name: Anonymous 2012-10-28 18:37

>>97
I'm not from ``reddit'', ``faggo''.

Name: Anonymous 2012-10-29 5:23

>>88
What's wrong with using the microphone input?

Name: Anonymous 2012-10-29 11:29

>>99
At least one retard would forget to turn up the microphone input volume, resulting in a generated key with ~2 bits of entropy.

Name: Anonymous 2012-10-29 11:32

>>100
Or to even connect a microphone, for that matter.

Name: Anonymous 2012-10-29 23:53

>>101
Or to even power on the computer, for that matter.

Name: Anonymous 2012-11-01 13:41

>>102
Or to even bump this thread, for that matter.

Name: Anonymous 2012-11-01 14:42

Name: Anonymous 2012-11-01 16:22

>>104
It's trivial to detect just by looking at the low bits of the image and noticing they're a lot more random than they ought to be.

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