Safari extensions corrupted

I'm attempting to install a Safari extension and I'm getting a error that says:

"1Password-4.2.5.safariextz is damaged and can't be open. You should move it to the Trash."

I thought maybe the 1Password was actually corrupted so I tried Ghostery and got the same error.

“Ghostery.safariextz” is damaged and can’t be opened. You should move it to the Trash.

Any ideas?

EDIT

I'm on Yosemite 10.10.1 - Safari 8.0