There is provided mechanisms for updating a private key of a host entity. The private key is based on parameters negotiated between the host entity and a key issuer. The host entity further has a group public key that is generated by the key issuer and associated with the private key. A method is performed by the host entity. The method comprises obtaining a need to acquire a new private key. The method comprises, in response thereto, performing a private key update procedure with the key issuer using the public key and the current private key, wherein parameters for the new private key are negotiated with the key issuer. The method comprises generating the new private key using the negotiated parameters.