The Basics of Cryptography

The Basics of Cryptography written by, tHe mAnIaC

(blacksun.box.sk)

version 1.0,

Converted to HTML by Penguin

Disclaimer

This guide is for educational purposes only I do not take any responsibility about anythinghappen after reading the guide. I'm only telling you how to do this not to do it. It's your decision.If you want to put this text on your Site/FTP/Newsgroup or anything else you can do it but don'tu can do it but don'tchange anything without the permission of the author.

A word from the author:

I hope you like my Text and find them useful.If you have any problem or some suggestion feel free to e-mail me but please don't send mails like"I want to hack the US government please help me" or "Tell me how to bind a trojan into a .jpg"Be sure if I can help you with something I will do it.

Table of Contents

What is this text about?

About Encryption and how it works

About the Cryptography and PGP

Ways of breaking the encryption

-Bad pass phrases

-Not deleted files

-Viruses and trojans

-Fake Version of PGP

1. What is this text about?

In this text I'll explain you everything about encryption, what is it, PGP, ways that someone can read your encrypted files etc. Every hacker orparanoid should use encryption and keep the other from reading theirfiles. The encryption is very important thing and I'll explain you how cansomeone break and decrypt your files.

2. About Encryption and how it works

The Encryption is very old. Even Julius Caesar used it when he was sending messages because he didn't trust to his messengers. You seeencryption is everywhere, when you watch some spy film you seethere's always a computer with encrypted files or some film about hackersrypted files or some film about hackerswhen the feds busted the hacker and they see all of the hacker's files areencrypted.

When you have simple .txt file that you can read this is called "plain text".But when you use encryption and encrypt the file it will become unreadableby the time you don't enter the password.This text is called cipher text.The process of converting a cipher text into plain text is called decryption.

Here's a little example:

Plain text ==>Encryption==>Ciphertext==>Descryption==>Plaintext

This example shows you the way when you encrypt and decrypt a file.

3. About the Cryptography and PGP

Cryptography is science that use the mathematics to encrypt and decrypt data. This science let you keep your files and documents safe even on insecure networks like the Internet. The cryptography can be weak and strong. The best is of course the strong one. Even when youuse all the computers in the world and they're doing billion operations in second you'll just needBILLIONS of years to decrypt strong encryption.

PGP (Pretty Good Privacy) is maybe the best encryption program to encrypt your files and documents.It work in this way:

When you encrypt one file with PGP,PGP first compress the file. This saves you disk space and modemtransmition. Then it creates a session key. This session key works with a veon key. This session key works with a very secure and fastconfidential encryption algorithm to encrypt the file. Then the session key is encrypted with therecipient's public key.

PGP ask you for pass phrase not for password. This is more secure against the dictionary attackswhen someone tries to use all the words in a dictionary to get your password. When you use pass phrase you can enter a whole phrase with upper and lowercase letters with numeric andpunctuation characters.

Ways of breaking the encryption

PGP has been written for people that want their files encrypted for people that want privacy. When you send an e-mail it can be read from other people if you use PGP only the person for whois the message will be able to read it.

Now you know many things about PGP and the encryption but you may like to know can someonebreak it and read your private Text and files. In fact if you use all the computers in the world to decrypt a simple PGP message they'll need 12 million times the age of the universe to break it. You see this is the BEST the encryption is so strong noone can break it. The people that program it has done their work now everything depends on you.

-Bad pass phrases

The algorithm is unbreakable but they're other ways to decrypt the text and read it. One of the biggest mistakes when someone writes his/her pass phrase is that the pass phss phrase is that the pass phrase issomething like : "John" "I love you" and such lame phrases. Other one are the name of some friendor something like that. This is not good because this is pass phrase not password make it longerput numbers and other characters in it. The longer your pass phrase is the harder it will be guessedbut put whole sentences even one that doesn't make sense just think in this way:Someone is brute-forcing thousands of pass phrases from a dictionary therefore my pass phraseshould be someone that is not there in the dictionary something very stupid like:

hEllowOrld33IjustwanTtoteLLtoev3ryon3thatI'maLamErandI'mahacKer666

This is easy to remember because it's funny and there are only a few numbers but you may not useupper and lowercase characters. I hope you know will put some very good pass phrase and be surenoone will know it.

Another mistake is that you may write the pass phase on a paper and if someone find it you'll looseit and he/she will be able to read your encrypted files.

-Not deleted files

Another big security problem is how most of the operating systems delete files. So when you encryptthe file you delete the plain text and of course leave the encrypted one.

But the system doesn't actually delete the file.It just mark those blocks of the disk deleted and free. Someone may run a disk recovery program and sti a disk recovery program and still see all the files but in plaintext.Even when you'rewriting your text file with a word editor it can create some temporary copies of it.When you close itthese files are deleted but as I told you they're still somewhere on your computer. PGP has tool called PGP Secure Wipe that complete removes all deleted files from your computerby overwriting them. In this way you'll only have the encrypted files on your computer.

-Viruses and Trojans

Another dangerous security problem are the viruses and the trojans. So when you infect with atrojan the attacker may run a key logger on your system.

*NoteA key logger is a program that captures all keystrokes pressed by you then saves them on yourhard drive or send them to the attacker

So after the attacker run it he/she will be able to see everything you have written on your computerand of course with your PGP pass phrase. There are also a viruses designed to do this. Simpy record your pass phrase and send it back to theattacker.

-Fake Version of PGP

Another security problem is the PGP source that isavailable so someone can make a fake copy of it that is recording your pass phase andsending it back to the attacker.The program will look real and it will work but it may also havefunctions you even don't know about.

A way of defending of these security problems is to use a trojan and a virus scanner.You shouldalso be sure your computer is clean from viruses and trojans when you install PGP and also be sureyou get PGP from Network Associates Inc. not from some other pages.

So now I hope you understand that PGP can't be braked but if you use it wisely and be sureyour pass phrase is good one, you're not infected with viruses or trojans and you're using thereal version of PGP you'll be secure.

of PGP you'll be secure.