Encrypting??

[WAnKeR]

Something like a simple substitution cypher (exchange A &Z, B&Y, C&X, etc etc etc) can normally be broken by hand in a matter of a couple hours or less. Computers can do it in less then a second.

Wtf does that mean...
this is like german to me...
its all just silly talk

[foxyloxley]

Crytography is the art of making YOUR information only readable by your recipient, the ability to crack the code is NOT the question, as ALL codes are crackable. What matters is how long you can keep your information secure. For example, you might want to keep your share dealings secure, but it only needs to be secure until the transaction is complete. So a simple code would probably suffice. But when you require the information to remain secure for years, then you call on the aforementioned 1024 cryp, this is unbreakable with KNOWN capabilities, and will therefore keep your secret till the grave ??
if this is German to you, I recommend Simon Singh's book on Cryptography ( The Science of Secrecy ) And if that fails, you might well be the most aptly named member I found so far.

[Tim_axe]

As everyone has pointed out, encryption can protect your files. As for how, it is done by completely changing the file around. Simple encryption related techniques that many kids in school probably learned while passing notes behind a teacher's back could have been changing letters of the alphabet with different symbols that only you and your friends knew. Relating to computers, basically you will replace something in a file with something else completely different, that only you and the person reading it know.

This can be done many different ways. One would be substitution, where you can replace letters directly, like replacing all of the letter A's with B's, B's with C's, etc., so that Z's would be written as A's. A message like "PASS THIS ON" could be written as "QBTT UIJT PO" by doing that. Of course that is very simple and could be cracked in very little time with our current technology.

There are other techniques, or ciphers / encryption algorithms, etc. Many current ones are of the public-key encryption type, such as RSA, PGP, etc. They are different from private-key encryption in that you have two keys, a private one that you keep secret, and a public one that you can tell anyone so they can send you messages. The public one can only send you messages, and only the private one can read the messages sent to you. While using public-key cryptography is much slower than traditional private-key ciphers, many companies found a way to speed it up and keep it secure using a combination of both. Basically, your file is first compressed (to reduce size and make it more random), then encrypted with a random private-key (not your private key from public-key cryptography yet) to produce the encrypted file. This uses the speed of private-key cryptography (don't get it confused with your private key in public-key cryptography). After you have that encrypted file and the key to decrypt it, it encrypts that key with the public key of the person you're sending the file to. So only they can decrypt the key that decrypts the file. (Hopefully you followed that okay)

Oh, and the reason that a one-time pad is considered uncrackable is because you can never be sure what was encrypted. Different message and key (one-time pad) combinations can produce the same encrypted output, and a person trying to guess the key (one-time pad) could run across millions of messages, but wouldn't know which one is right since they don't know the original key, and have millions of keys that *could* be it (along with millions of different messages).

Sorry I don't have any links to reference material or websites. My bookmarks are empty... Searching threads here on AO that list different free E-Book websites could be useful, so good luck.

[Ohm]

I'm trying to write my own encryption program, but I need to find some specific information on the guts of the encryption algorithm. I'd like a public key encryption program, something like rsa, but i need to understand what each variable is in the equations. Most sites that I've found are either to vague for my purposes or explain only half of the information. If anybody's got any got sites or information, please let me know.


Ohm

[WAnKeR]

so i can encrype all of my files?

[souleman]

you can't encrype anything.....

you can encrypt all text files/pictures/etc... you can also encrypt executable files, you you have to decrypt them to run them.

[WAnKeR]

ohh..ok...its to much to remember..so screw it..ill just leave me the way they are...but thnx for the help

[Ennis]

From one of my tutorials, hope it helps you out.



|-Encryption-|

Just a note, check out Negative's tutorial on Encryption, this is a very basic rough guide and I just posted it as I wrote it a long time ago and thought I'd put it up!

Basic Encryption

______________________________________________

1=what is encryption?
2=basics of encryption and decryption
3=cryptography and pgp
4=security

1. what is ENCRYPTION
______________________________________________

This text deals with encryption, what exactly it is and PGP, as well as how others can decrypt your encrypted files. Encryption is a very useful resource to the hacker that wants to keep his exploits private. By reading
this text carefully you can safeguard your files from attacks.


2. the basics of encryption and decryption
______________________________________________

Encryption means making a simple .txt file unreadable. when you write a simple .txt file it is in "plain text".
however if you encrypt this file it becomes unreadable. Before a password is entered this text is known as cipher text. When however you decide to change this cipher text back into plain text it is called decryption.

EG. ENCRYPTION-->turns text into
CIPHER TEXT-->which can be changed by
DECRYPTION-->into good ol'
PLAIN TEXT-->you can now read your file..

3. cryptography and PGP
______________________________________________

Cryptography is a mathematical science and well in the more english sense of the word is the uncovering or conversion of cipher-text.
In maths it means to encrypt or decrypt data so maths is strongly associated with cryptography.
It is possible to secure files so well it could take years and years to decrypt that is why encryption is so important on an insecure place such as the internet.
One of the best encryption programs on the net is PGP [pretty good privacy].

get it at: www.pgp.com

its features include compressing the file to save you space. it then creates what is known as a session key.
This session key uses a private encryption algorithm that encrypts the file.
The two keys ivolved the session key and the recipients key are encrypted together.

PGP does not use normal passwords but long passphrases which can involve both lower, upper and number characters to deter dictionary attacks from password crackers.
Most password crackers will not contain word-lists with such characters.

4. security
______________________________________________

Encryption if used right can make your information unbreakable but there are
ways in which its misuse can lead to succesful "cracks" on your private information.

I will begin with trojans and virii

If your computer became infected with a trojan the attacker may run a key logger [program that collects all your keystrokes and sends them to your attacker]. The attacker will then be able to see your passphrase, this may also occur with certain viruses.

Next stupid passphrases/words
A very obvious mistake made by people is a very simple password is used and the attacker simply guesses it. The whole encryption process is useless with these passphrases.
Examples of bad passphrases include
-your name
-god
-i love you
-your area
If someone is using a brute force attack on you such easy popular passwords will be included in some text file and they will achieve access.
Try a long one with numbers as well as upper and lowercase letters.
EG. d0Ntu53sTUp1dP4Ssw0rD5
that type of stuff, something youll remember.
BUT dont write it down on pieces of paper near you computer and
DONT USE THE SAME PASSWORD ALL THE TIME....
or else if a hacker gets into one file hell get into every password protected file/site/e-mail account you have!


__________________

[WAnKeR]

thnx

cheers

[Noia]

Encrypting any thing is 1024 RSA is like encasing your computer in a 2km^2 block of cement and giving some one a needle to get through it all...

There are alot of good Tuts on Encryption here on AO, just search

- Noia