@node Encrypted area
@section Encrypted area packet

@ref{Multicast} area messages contains the encrypted packet, that is
completely similar and have the same format as an ordinary
@ref{Encrypted, encrypted packet}. But instead of the node's identity,
area's identity is used as a recipient.

For example when @code{nodeA} sends multicast packet with file
transmission and @code{nodeB} is the area's subscriber, then
@code{nodeA} has an encrypted packet to the @code{nodeB} in the outgoing
spool directory:

@verbatim
ENCRYPTED PACKET (sender=nodeA, recipient=nodeB) WRAPS
  PLAIN PACKET (type=area, path=AREA ID) WRAPS
    ENCRYPTED PACKET (sender=nodeA, recipient=AREA) WRAPS  <-- MsgHash
      PLAIN PACKET (type=file, path=FILENAME) WRAPS
        FILE CONTENTS
@end verbatim

Area's message identity is the BLAKE2b-256 hash of header of the area's
packet encrypted packet.