i seriously don't get it this

i've noticed diferent ppl over time postin a string of chars saying.. i made an encryption proggie... can you crack this...

how in the hell can you crack a "string" if you have no idea about the method of encryption... let me show you and example of .... look at this example

this would be my method...

ei... there are basically 2 types of letters in the alphabet:
....curved and not curved.... i guess it would really depend on the type of font you are using but for now let assume that all the fonts are the same...for this example we will only consider caps

so curved would be: BCDGJOPQRSU
not-curved would be: AEFHIKLMNTVWXZ

do you see the difference... so my key for encryption would be like this "@" for curved and "#" for not-curved ... plus we would be counting from backwards...

A B C D E F G H I J K L M N O P Q R S T U V W X Z

MIRROR = #7#10@3@3@6@3
SPEAKER = @2@5#13#14#9#13@3

now imagine that i will have 4 criteria like

curved w/ closed circle............................. BDOPQR
curved not closed.................................... CGJSU
not curved w/ 90 degree angles............. EFHILT
cuved w/ 45 degree angles.................... AKMNVWXZ

all this is basicaly off_the_wall ... crazy thing that i just made up but the challange is how in the world can you "decrypt" it... what would be your resoning... my point is that posting random string here to decrypt them is waste of time

Excellent point... and another point to add on to that. People always say... Check out my NEW encryption and see if you can crack it. Well, 99% of the time, it is nothing new. Before you develop something new, make sure it is something new. If you really want to become an authority, take the time to do some investigation and find out what has already been done and if it was broken before, and how it was broken.

:drink:

LOL, when you send something that is encrypted to another person... Lets say through E-Mail and its intercepted. It can be decrypted. Thats the point of creating different/better ways of decrypting. If they wern't possible to decrypt then there would only be a need for 1 type of encryption. But as you can see there are many ways to encrypt as well as many ways to decrypt them.

So in response to your question. You don't usually see and E-Mail with an ecrypted text that includes a way of decrypting it. That part is left for the "cracker/hacker".

Unless the program is bases on an Enigma type base then it usually is very easy to crack with the right knowledge.

All that really needs done is to take the text, convert it to ASCII and find the pattern in the numbers.

So even if you know the method or not it still is very possible.

you have to realize that my example is very simple and took me 0.5 sec to come up with in my opinion the only pattern you can find is if the encryption is based on mathematical algorithm... my example is NOT... it's based on clever gimmick ... something a person understands but computer might not (yes i know about handwritting recog.) but if you take 50 "clever tricks" like this and layer them on top of each other .. basically make them as confusing as possible and then write a program which run each "clever" function on the output of previous function... what you are going to end up w/ is garbage text w/out any pattern that noone but you has any idea how to crack. just like some of the stuff posted here...

you could find a pattern such as the @ and the # i belive. I may be totally wrong though. I have very little knowledge in the filed of decryption. Sorry if i'm wrong.

if given enough examples and and alot of time you could find a pattern in any encrytion and break it the trick to good encryption is to make the number of examples needed to find the pattern almost immpossable or at least improbable to get.

Hmmm... cryptanalysis on modern encryption schemes isn't always about pattern recognition. Take for example DES, or RSA (or anything based on those methods). Using any method that employs transposition (as opposed to substitution which is what you're discussing above), it diffuses the normal patterns and distribution of letters to the point that pattern recognition doesn't get you much.

A perfect example would be columnar transposition. Check this link for a good description and how-to. I believe it was first used by the Spartans.. to the casual observer, it's still hard to wrap your brain around.

l00p

I think that etruscan has a point.

In the real world you would know who the message was from and who it was to (not necessarily the individuals, but the organisations)

You would also know what the subject matter was likely to be and the language being used.

You would also know the encryption method likely to have been used, so all you would really be looking for was the key.

As a totally ridiculous example: suppose I gave you some strings or blocks (yes, I am that old :D ) that were total gibberish, and asked you for the message therein, you could take 10 times the age of the Universe, and still not have an answer, simply because there wasn't one?

At the end of the day, you have to assume that meaningful encrypted communications can be decrypted. All you do is buy time and make it very expensive. The secret is to have the encryption strong enough to make the information outdated enough to be useless by the time it can be decrypted.

This is why Governments have spies............they want intelligence in real time.

Cheers

i do, agree w/ the fact that given enough time all the possible combinations of the clear text could be compared to encrypted text but... on what basis... what if i'm creating a key which is based on a presence & order of certain letters in a 1.7 minutes of dialog from a Godfather ...and then running that through filter based on percentage of white, red & black colors on a 16 oz can of Bud... it's silly to think that somehow through enough computing power you can find a key made by human being... we cannot pull primes out of our ass but we are too inconsistent for logic and mathematics

Given a good enough programmer/cryptographer with a good PC you could decrypt just about any thing. The reason is that anyone that spends enough time to learn how to really encrypt something must have some sort of logical mind….so all you would need to do is to find a key…witch takes you back to the computer…just think what would have happened in WWII if they had the tech base that we have know and all we can do is get better from here.

sorry if this does not make sence as I have had toooooo much beer for my own good.

Enigma in WWII was the classic example of how important it was to know what hardware was used to do the encryption. In fact Poland provided an Enigma machine to the British at the start of the war, together with their cryptographic expertise, but no one at that time realised how important this was.

Later on, one or two enigma machines were captured, which meant that the team of mathematicians at Bletchley Park using primitive computers were able to continue to crack it.

In todays world, if you know that the encryption is being done on a normal PC, that should give you a head start, as the sort of questions you would ask is what OS is it using?
What are the weaknesses of this OS?
Is it a commercial algorithm or something else?
Etc.. etc ...

I'm not even into cryptography, but i'll throw in my take on this.

Give someone a string of random characters and they'll never break the encryption, or "crack it" so to speak. As far as I understand encryption, it relies on an algorithm, be it mathematical or otherwise, it's still an algorithm. The data is encrypted either using the algorithm alone, or more securely using a key/password that the algorithm incorporates. There are only a few ways to decrypt/crack the encrypted data.

1. Have a keyed algorithm and the proper key/password (decrypt)

2. Have an unkeyed algorithm and encrypted text (crack)

3. Have unkeyed encrypted text and the decrypted data (crack) You could determine the algorithm

4. Have the keyed algorithm (crack)

Beyond those 4 methods, your only way would be to brute force your way in. Even then, it'd be nearly impossible. Even with method 4 you would have to brute force your way threw every possible key, until the text made sense, depending on the length of the key this could take ages.

So when someone says here's text I encrypted, decrypt it for me. Tell them to F#$% Off. There are a lot more useful uses of your time. If I'm wrong on this, feel free to correct me, but this is how I see it.

In reply to HTRegz,

I don't really agree with you.

Let's take a simple example where you are running PGP on your PC.
Unless you are very careful, there will be some traces of the keys left on your PC.

So your encryption is worthless if either:

Your PC is infected with a trojan/virus - obviously shouldn't happen to people here :),
or you allow someone else physical access to your PC, in which case anything goes, or something you are doing leads the relevant authorities to make a raid, and seize your PC.

Brute force doesn't work, but how do you know what the mathematicians are getting up to?
ru absolutely sure prime numbers are randomly spread (which is what PGP relies on) ??

Just some thoughts, as this isn't as simple as you might think.

I agree with you it is normally a waste of time trying these challenges.
I think you will find that the likes of NSA have seen them all before ...

HTRegz

You have a point, if the string is truly random it will not be broken, not even by the intended recipient :) For this to be possible there has to be an algorithm/key.................that means it can be broken.

This follows on from my previous comment that if the string is nonsense, no one will find a message in it :)

In the old days of transmissions by radio, in blocks of numbers, some of these blocks would be dummies, to introduce an element of randomness. The recipient would know which ones to ignore depending on the time/date or whatever.

After a while, the codebreakers would probably identify these as well, but by that time the information in the message was past its merchandising/sell by date. This detection was based on hunch and experience, as opposed to brute force methods, which I would have thought would be vulnerable to this sort of subtrefuge?

Cheers

if you did notice in my example in the first post the clear text is also used as a key to the encryption and decryption (or better yet... the properties of the text). which means that if i change the clear text i'm also changing the key... therefore the method MUST be know or at least aproximated in order to have any valid starting point to start cracking. if you combine that w/ a techniqe that results in different (readable) plain text depending on the method you use .. that results for example, in deniability for certain cases where encryption key is used as proof of identity.... imagine an encrypted text that will give you a A-bomb plans or Cat in a Hat depending on a method of encryption... but that as well as everything else is old news..

etruscan I absolutely agree with you. There HAS to be a starting point for any real hope of deciphering any kind of encryption. - Short of me giving an example of shifting the alphabet or any kind of child play attempt at hiding a message.

Popular belief that someone can take a set of data and decrypt it on a pc is science fiction or fantasy. You can site examples of previous successful hacks of the Enigma Device and DES, but none of those were decrypted using just an example of each devices data output. I am talking about random data only as intercepted by some means. Not physical access to the encryption/decryption engine. - Just plain old data only.

To say you could decrypt:

ewqpoicrqpweoirupq23804n v284ty 4v8qyq 89pewr p89q2b v3q

out of thin air is not possible. I like your bud can analogy. Sure you could look for key information like repeated patterns etc. Then start plugging away with mathematical solutions and complex arrangements of random data and try and interpret the result and in 1000 years come up with something, but what? You couldn’t have a gauge to verify anything. It could say “white bunny slippers” or “I want a peppermint” It would just be a guess. Without a stating point it's pointless.