Applies to these editions of Windows Vista

Change the key you use to encrypt files and folders

You might want to change your Encrypting File System (EFS) key if:

You have encrypted files on two computers that require two different keys, but you want to use just one key.
Your organization asks you to change keys regularly.
You start using a smart card to encrypt your files.

An encryption key is always associated with (or linked to) an encryption certificate. To change your key, you have to change the certificate you use for encryption.

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To select a different file encryption certificate

Open User Accounts by clicking the Start button , clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.
In the left pane, click Manage your file encryption certificates.
In the Encrypting File System wizard, click Next. The wizard will display your file encryption certificate in the Certificate details box.
Click the certificate you want to use, and then click Next.

If you have more than one file encryption certificate, and the one you want to use is not displayed, click Select certificate, click the certificate you want to use, click OK, and then click Next.
If the certificate is not backed up, you should back it up now. Click Back up the certificate and key now, type or browse to the location where you want to store the backup, type and confirm a password, and then click Next. We recommend storing the backup on removable media such as a disc or USB flash drive and protecting the backup with a strong password.
Select the check boxes for the folders you want to update with the new encryption certificate, or select the I'll update my encrypted files later check box, and then click Next.

To create a new encryption certificate

You'll need to know what type of encryption certificate you need. Contact your network administrator for more information.

Open User Accounts by clicking the Start button , clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.
In the left pane, click Manage your file encryption certificates.
In the Encrypting File System wizard, click Next.
Click Create a new certificate, and then click Next.
Select the type of certificate you want to create, and then click Next.

To back up your encryption certificate

Open User Accounts by clicking the Start button , clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.
In the left pane, click Manage your file encryption certificates.
In the Encrypting File System wizard, click Next.
Click Use this certificate, and then click Next.

If you need more details to identify the certificate that is listed, click View certificate. If you want to choose a different certificate, click Select certificate, and then click the certificate you want to back up.
Click Back up the certificate and key now.
Type or navigate to the location where you want to store the backup. We recommend that you store the backup on removable media such as a disc or USB flash drive.
Type and then confirm a password for the backup file, and then click Next. We recommend that you protect the backup file with a strong password.
Select the I'll update my encrypted files later check box, and then click Next.

To update your encrypted files with the encryption certificate you have created or chosen

Open User Accounts by clicking the Start button , clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.
In the left pane, click Manage your file encryption certificates.
In the Encrypting File System wizard, click Next.
Click Use this certificate, and then click Next.

If you need more details to identify the certificate that is listed, click View certificate. If you want to choose a different certificate, click Select certificate, and then click the certificate you want to use.
If the certificate is already backed up, click Back up the certificate and key later. Otherwise, follow the instructions above to back up your encryption certificate before you use it to update your encrypted files.
Select the check boxes for the folders you want to update, and then click Next.
To see if your files were updated successfully, click View log.