[vb6] Encryption, Write/Read, Saving/Opening File Extensions

Hi Guys, first things first, my explaination. Im making a program that can either open a folder or an individual file, encrpyt it, and save it with my programs extension, and then be reopened with a password promp. Now since its such a large thread range, il use a numbering system, and depending on what advice or help you have, use the number :) .

1. Encryption

I know how to encrypt, done tons of projects. What i want to know on the subject is, techniques. The calculations that all the large companys are using (ovbiously no uniques, but you get the idea).

2. Write/Read

Im also quite familiar with these functons. Im looking for and nics and tricks that might contribute to the editing of files.

3. File Extensions

This is where i need the most help. Creating a file from scratch. And how to make a file extension reconize my program. (also knowing how to "open" an extention properly.

Any help is greatly appreciated, il be giving credit to unique work, thanks,
___
Dan

Quote:

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Originally Posted by MeTTa@

1 "What i want to know on the subject is, techniques. The calculations that all the large companys are using"

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Sure... don't write the password on a sticker paper and stick it on the monitor...
Well, honestly I don't quite understand what your question is...
Just make your own encryption, or use a standard encryption.
I prefer making my own, this way the cracker person does not even know where to start on breaking the encryption. If you use a standard encryption, then the cracker can posibly find a tool on the internet to crack the encryption.

For points 1 & 3, see this thread:
http://www.vbforums.com/showthread.php?t=232284
It shows how to make a very strong encryption, and how to make your own file format.

2. Well, if you want best performance for reading/writing, use API...

Thanks, For encryption, im talking abotu calculation techniques. Ovbiously something other than + 1 x 2.

Quote:

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Originally Posted by MeTTa@

Thanks, For encryption, im talking abotu calculation techniques. Ovbiously something other than + 1 x 2.

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Well, that varies from encryption to encryption... I don't think there is a standard on how to calculate for encryption, if there was, then all encryptions will be the same...

Well when someone says 24bit encryption, what do they mean. How is it measured? I just looked at your project, that is nuts. How could i make it unique and decrypte it?

Quote:

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Originally Posted by MeTTa@

Well when someone says 24bit encryption, what do they mean. How is it measured?

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It basically says what is the key length (24 bit = 3 bytes).
Or... it says how much you have to decrypt in order to get something (3 bytes).
Or... it says it takes a maximum of 2^24=16777216 tries in order to break the encryption using brute force method.
Brute force method is when you try every single password possible to break the encryption. So for 24 bit you have to try 16777216 different passwords to break it.

A 24 bit (2^24=16777216) password can be broken in a few hours, maximum a day.
A 128 bit (2^128=3.4028236692093846346337460743177e+38) password probably takes at least a life time to break it.

NOTE: That every extra bit, takes double the time to break the password/encryption.
For example,
2^24=16777216
2^25=33554432
2^26=67108864
etc...

Quote:

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Originally Posted by MeTTa@

I just looked at your project, that is nuts. How could i make it unique and decrypte it?

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The function that does the encryption is CryptFile.
To make it "unique", modify this line:

VB Code:

Put OutFileNum, , StrXOR(InBuff, Left(HASH(Password & "?" & K, False, Algorithm), Len(InBuff)))