How do I change my master password?

1P4 > Preferences > Security Change Master Password.

Just be aware of two things:

1. If you sync to any iDevice you will need to check that the change does in fact sync. There have been some cases where it hasn't so that you need manually to update the master password on the iDevice.
2. Changing your master password does not re-encrypt your 1P4 data. If you wish to re-encrypt your data with a new key created from your new master password the procedure is a little more complex.

Stephen

I think I'd better wait for an AgileBits expert to answer that question! In my eyes, if you have a weak master password originally then change it to a strong one re-encryption doesn't matter (because the strong master password protects your data, even if that data is encrypted using a key derived from the original weak master password).

Please don't rely on what I'm saying: wait for something more expert from one of the AgileBits people!

Stephen

One good reason the re-encrypt your data when changing your master password from a weak one to a strong one is that the data remains accessible under the old password, as well as the new one, if you don't re-encrypt. If anyone guesses that weak password, they would have access to your data.

Edit: Oops! @Stephen_C's link gives you lots more good information. I should have read his post more carefully.

The key paragraph in @khad's post, about why you would want to re-encrypt your data, at least for me, is:

Since your Master Password protects a secret key that never actually changes, old copies of your key files (1password.keys, .1password.keys and encryptionKeys.js) will remain protected only by your old Master Password. Because your more recent data are encrypted with the same decryption key, then even those can be gotten at by cracking an old Master Password.