represent `nbf` as a number containing a NumericDate value.

Condition: if `nbf` is present

Its value MUST be a number containing a NumericDate value.

include `nbf` as a top-level introspection-response member containing an integer timestamp measured in seconds since January 1, 1970 UTC and indicating when the token is not to be used before.

nbf OPTIONAL. Integer timestamp, measured in the number of seconds since January 1 1970 UTC

allow a small amount of leeway, usually no more than a few minutes, to account for clock skew.

Condition: when processing `nbf`

Implementers MAY provide for some small leeway, usually no more than a few minutes, to account for clock skew.

accept the token for processing before the time identified by `nbf`.

Condition: when applying the `nbf` semantics

the JWT MUST NOT be accepted for processing

require the current date and time to be after or equal to the not-before date and time listed in `nbf`.

Condition: when processing `nbf`

the current date/time MUST be after or equal to the not-before date/time