Ubuntu
ecryptfs-utils package

Changing login/mount passphrases?

Asked by Rizlaw

I have two questions regarding pass phrases in the new encrypted .private folder:

1. If you decide to change the user login pass phrase used to initially create the "private" folder to something more secure, will such a change prevent you from accessing the data in the "private" folder on the next log on? As I understand it, the user's log on pass phrase is used to decrypt the mount passphrase to gain access to the data. If the user's log on password changes, it would seem that the mount passphrase might no longer be decrypted - hence the data, in the private folder, unrecoverable.

2. Conversely, is there a way to change the mount pass phrase without losing any encrypted data?

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Rizlaw (rizlaw) said : 		#1

Answer from Ubuntu Wiki: https://wiki.ubuntu.com/EncryptedPrivateDirectory#head-4a2aa7460fdca18bfe78bb1283becff406bbc13c

Q. "What will happen when a user changes his login password (via GUI or passwd command)? Are we still able to decrypt the key needed for mounting ~/Private? If so... how? (steven3000)"

A. "See section 7 Implementation of this page where it says, "The pam_ecryptfs.so module handles rewrapping of mount passphrases on password change." See also ecryptfs-rewrap-passphrase-- DustinKirkland"

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gaax (gaax) said : 		#2

We can imagine that scenario:
My laptop was stolen.

1. Robber crack a root password
2. Change password for my default user (chpasswd)
3. login in to new password on my default user

The question is: They have access to secure data in private folder? I think answser is: Yes.
So, my secure data will be decrypted.

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Jakob Unterwurzacher (jakobunt) said : 		#3

You absolutely need the correct wrapping password to change it. Changing the login password by force will NOT open up the encrypted directory.