Decrypted file corrupted (EFS).

[barion00]

I was installing a new HDD in Windows XP pro (sp2) laptop which
includes several encrypt folders originally.

First, I copied all files under My Documents folder to USB drive.

Second, exported all Certificates from XP Laptop to my desktop (Win2000
pro) and decrypted during fresh windows XP installation process on
Laptop.

Third, I copied decrypted documents back to the laptop.

Once, I copied back to my documents, a lot of files are corrupted. From
MS site, I guess that may because of the Advanced Encryption Standard
(AES) algorithm of Windows XP (not working for Windows 2000). I do not
have duplicates for the corrupted files.

Can someone tell me there's any way to recover those corrupted files?

 

[Steven L Umbach]

I am a bit confused as you say that you decrypted the files before you
copied them back to the laptop at which point encryption would no longer be
part of the scenario as they would be ordinary files. If the files were
still encrypted while on the W2K computer try using the built in NTbackup to
backup and then restore the files on the XP Pro computer making sure that
the service pack is installed on it. Also make sure that you have full
control permissions to the files before you try to decrypt them. Do the EFS
encrypted files still possibly exist on the old hard drive for the
aptop?? --- Steve

 

[barion00]

Well, I did decrypted files before copied them back to XP Laptop. BUT
SOME OF FILES ARE CORRUPTED. I am not sure what the reason is. It
worked fine.

I am suspecting that I encrypted using AES (since laptop was XP sp2
installed) and decrypted using old fashioned algorithm in Win2000
somehow...

I had Sp4 installed in win2000 and sp2 installed in XP and
administrator account used with proper certificates.

Unfortunately, I do not have old HDD. I had to return it to their
service dept.

 

[Steven L Umbach]

OK. I think I understand now in that you decrypted the files while they were
on the Windows 2000 computer and many of the appeared corrupted and I agree
with your assessment of what probably happened as explained in the KB
article below. From what I know you probably are going to be out of luck
with those files. I would however suggest that you also post in the
Microsoft.public.security.crypto newsgroup for feedback and if those file
are important try contacting the service dept. ASAP to see if you can get
that drive back even if just temporarily. --- Steve

http://support.microsoft.com/default.aspx?Scid=kb;en;329741

 

[barion00]

Thanks for your advise.

I posted to Microsoft.public.security.crypto group.

Contacting Service won't work, since I erased old HDD..