Keys object to derive keyset id from.
Optionalunit: string(optional) the unit of the keyset.
Optionalexpiry: number(optional) expiry of the keyset.
(optional) version of the keyset ID. Default is 0.
(optional) true if the keyset ID should be derived as a deprecated v0 base64 keyset ID.
Keyset id of the keys.
Returns the keyset id of a set of keys.