Cryptograhpic sytems??!! ... Help please

kenny504

Ok i'm just getting my foot wet in security so bear with me. I understand cryptography and the various cryptograpic systems...but i would like to know how the hell is it implemented in the first place. I mean is there a program on a cd that you run on a system and select the files u want encrypted with this certian cryptography scheme.....??..

Is there specific software out there that says.. Hey this is a RC4 encryption software that allows you to encrypt your keys or data. Just put the cd in and select what you want encrypted???...Is it like that??....How are all these different chypering algorithms and methods actually aplied in the real world.

I just got a couple cbt's for sec+ and also ceh...have'nt gotten very far with sec+ actually stuck on cryptography..understand the concepts just dont kno how it is applied ......I have like 12 more chapters to go..i probably will get the answer later..But I'll like to see some opinions..

Help please!!!

toughbaloch

Crytographic algorithms are implemented in software and hardware both. For example if your using SSH, the SSH client and Server have builtin encryption algorithms , they negotiate on which one to use, then your session is encrypted using that encyrption say.
OpenSSH supports 3DES, Blowfish, AES and arcfour as encryption algorithms. One of them is default and you can change the default algorithm. Browsers, webservers and all other communication software come with encyrption algorithms built into them more then one. If you are witing your own software and you want to authenticate and encrypt the data when clients communicate you can use cryptographic API(application programming interface) which are made available by programming languages through libraries or you can find implementation of cryptographic algorithms by other developers in different language. Try googling RSA encryption API in C/C++.

Thanks,
Ahmed

sprkymrk

Maybe a very simple example will help;

When you go to a secure website using the https protocol, did you first have to insert a CD and install something, and then tell it you want to encrypt your packets to and from that website? No, the encryption is built into the protocol.

Another example, when you create a VPN using MS "Create a new connection" wizard, you feed it a little information (like destination IP, etc), but once you launch the VPN your data is encrypted based on the protocol you chose (PPTP, IPSec/ESP, etc.).

An example of "data at rest" encryption is MS EFS. In that case you do have to tell your computer "encrypt this document" or "encrypt everything in this folder", but otherwise the encryption/decryption process is invisible.

This might be over simlifying it a bit because in some cases, like PGP, you do have to put forth a little more effort. Usually it's just a matter of enabling the option/technology through the OS, but in some cases you need to set up an entire infrastructure to support it as in PKI.

A good hands on practice lab would include setting up a server and 2 clients on your network. Use a hub to connect them for simplicity (rather than a switch). Install wireshark or ethereal on client2, set up a basic web page or FTP server on the server. Fire up ethereal/wireshark to capture packets in promiscuous mode on client2, then have client1 upload/download from the FTP site or access the web site on the server. See what you captured on client2.

Now enable IPSec between server and client1 and repeat the excersize. That will give you experience setting up IPSec, a web server/FTP server, and reading captured packets all in one lesson. Not including the time to set up the server/clients, the whole lab should only take 90 minutes, unless you run into trouble setting up IPSec which is (admittedly) not very intuitive. There is a lot of documentation on MS for doing it though. Good luck and feel free to ask more questions.

kenny504

Wow...i get ya. I just thought it wud b more interevenous than that...guess not...Thanks.

Ok I'll erase this paragraph..i think i understand now..thanks Ahmed

Ye Gum Noki

THIS is a great tool to learn about encryption:

http://www.cryptool.com/

Mr. Ye