[Question brought here from the security section]
Is there any easy way I can decrypt a folder that has been encrypted with Windows 7? I am using Ubuntu 11.10 to decrypt the folder.
Files encrypted with EFS can only be decrypted by using the RSA private key(s) matching the previously-used public key(s). The stored copy of the user's private key is ultimately protected by the user's logon password. Accessing encrypted files from outside Windows with other operating systems (Linux, for example) is not possible — not least of which because there is currently no third party EFS component driver.
EFS - Encrypting File System - is native to Windows & Microsoft. Microsoft have not released this as opensource - and no-one (as yet) has clean reversed engineered this.
I'm afraid - the only way you will be to decrypt a windows 7 file and folder encrypted using native windows encryption is via windows itself.
Depends on what you encrypted the file with. LUKS, truecrypt, and gpg are all cross platform.
Windows - freeotfe
Ubuntu - To set up an encrypted partition in Ubuntu, using /dev/sda4 as an example,
sudo cryptsetup -h sha256 -c aes-cbc-essiv:sha256 -s 256 luksFormat /dev/hda5 sudo cryptsetup luksOpen /dev/hda5 crypt mkfs.ext4 -m 0 /dev/mapper/crypt
# graphical gksu gedit /etc/crypttab #command line sudo -e /etc/crypttab
Add a line for your crypt
crypt /dev/hda4 none luks,timeout=30
# graphical gksu gedit /etc/fstab #command line sudo -e /etc/fstab
Again, add a line for your crypt in
/dev/mapper/crypt /media/crypt ext4 user,noauto 0 2
Make a mount point
Now you can mount it with
GPG will run on both windows and Ubuntu
gpg -c file
gpg -c file command only encrypts the file, it does not delete the original source file, so you may need to (secure) delete it.
For windows try gpg4win