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 Post subject: Decryption in Win 7
New postPosted: Sun Mar 04, 2012 10:25 pm 

How to decrypt files and folders in window 7 that has been encrypted in window XP sp3.
Actually i have encrypted some folders and files for security purpose in window XP sp3 but now i have installed window 7 without decrypt the same folders and files in same machine, so please provide me the possible sollution.
Thanks.


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 Post subject: Re: Decryption in Win 7
New postPosted: Tue Mar 06, 2012 1:09 am 

Try this

http://mintywhite.com/windows-7/7securi ... s-windows/



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 Post subject: Re: Decryption in Win 7
New postPosted: Tue Mar 06, 2012 9:48 am 

UVAIS, that only works where there is a KEY (Certificated Key) to unlock (Decrypt) the Locked (Encrypted) folder or file., or even a system.

@SachinVishvas - Do you have the certificate key to unlock the encrypted file/folder? If you, you can use the link UVAIS provided. If you don't have the certificate key, then, you would need to brute force it to decrypt it, only if you don't remember the password you in which you encrypted in the first place.

I just need a little clarifications, did you Upgrade from Win XP SP3 to Win 7, or straight to Format and then Win 7? It wouldn't matter, the key points here is that you need the certificate key...



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 Post subject: Re: Decryption in Win 7
New postPosted: Tue Mar 06, 2012 1:25 pm 

I hate to say it, but you are in a world of trouble. You should have decrypted the machine before you installed Windows 7. During your installation you wiped out your encryption key file. The only possible way I can see to decrypt these files is if you have the .pfx (Personal Information Exchange) certificate file and the accompanying password. Then you could apply it to your hard drive. Windows 7 has a feature that constantly nags you to back up this .pfx certificate. Listening to your plight, I'm glad I have backed mine up.

Since Windows XP SP1, the default encryption type is EFS (Encrypting File System), which uses a 256-bit AES form of security. A brute-force attack is logistically impossible in this scenario, and would take years even if you had a room full of servers all dedicated to hacking the encryption. Read this entry on encryption: "If a device existed that could brute-force a 56-bit encryption key in one second, it would take that device 149.7 trillion years to brute-force a 128-bit encryption key" The amount of time needed for a similar device to hack 256-bit encryption is 50,955,671,114,250,072,156,962,268,275,658,377,807,020,642,877,435,085 years. You read that correctly. From the same article: AES permits the use of 256-bit keys. Breaking a symmetric 256-bit key by brute force requires 2128 times more computational power than a 128-bit key. A device that could check a billion billion (10^18) AES keys per second (if such a device could ever be made) would in theory require about 3×10^51 years to exhaust the 256-bit key space. Quantum computers are needed to crack such complicated encryptions in a more practical length of time.

Thanks for this post by the way - I learned something today!



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