Dear abdrahman elkafil,
I think if you take a look at the Tryton LDAP Authentication module  you will probably see how an external authentication mechanism can work with Tryton. Maybe you can have your blockchain style authentication produce some kind of user object that is mapped to a Tryton user.
There's also a SMS Authentication that you can find here.
On Thu, 2019-05-02 at 15:17 +0100, abdrahman elkafil wrote:
we want to authenticate to gnuhealth with blockchain technology, how can we link our smart contract in ethereun with gnuhealth? can somebody help