All date/time durations in the config= uration files are specified as defined by ISO 8601.

Durations are represented by the form=
at **P[n]Y[n]M[n]DT[n]H[n]M[n]S**. In these representations, t=
he **[n]** is replaced by the value for each of the date and t=
ime elements that follow the **[n]**. Leading zeros are not re=
quired. The capital letters **'P', 'Y', 'M', 'D', 'T', 'H', 'M', and =
'S'** are designators for each of the date and time elements and are=
not replaced.

- P is the duration designator (histor= ically called "period") placed at the start of the duration representation.=
- Y is the year designator that follow= s the value for the number of years.
- M is the month designator that follo= ws the value for the number of months.
- D is the day designator that follows= the value for the number of days.
- T is the time designator that p= recedes the time components of the representation.
- H is the hour designator that follow= s the value for the number of hours.
- M is the minute designator that foll= ows the value for the number of minutes.
- S is the second designator that foll= ows the value for the number of seconds.

For example, "**P3Y6M4DT12H30M5=
S**" represents a duration of "three years, six months, four days, t=
welve hours, thirty minutes, and five seconds". Date and time elements incl=
uding their designator may be omitted if their value is zero, and lower ord=
er elements may also be omitted for reduced precision. For example, "**P4Y**", "**PT5M**" ar=
e all acceptable duration representations.

A year or month vary in duration depe=
nding on the current date. For OpenDNSSEC, we assume fixed values

- One month is assu= med to be 31 days.
- One year is assumed to be 365 days.