GELI zfs encryption removal

Hi,

I'd like to remove GELI encryption. It was installed
when the OS was installed; the option to encrypt data was
chosen when auto-zfs was selected.

At the moment, when it reboots, it prompts for the GELI
passphrase, which I have to enter from the console[1], and it
then boots normally. [1] is a nuisance to access, so I'd like to 
(safely) remove it. Is this possible, without having to transfer 
all the data out, reformat, then transfer it all back in again?

thanks in advance,
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