According to the invention, a method for protecting digital television
from unauthorized digital receivers within a population of digital
receivers is disclosed. Each digital receiver in the population has a
unique identifier. In one step, provisioning information is received from
a subset of the population of digital receivers indicating that the
subset is potentially within range to receive digital television from a
broadcaster. First decryption information is distributed to the subset of
the population of digital receivers. The first decryption information
allows for potentially decrypting a plurality of programs coextensively
in time. The unauthorized digital receivers are cryptographically
excluded from using the first decryption information. A first program is
encrypted using a first method that is cryptographically related to
second decryption information. The first program is sent. The second
decryption information is distributed and cryptographically secured with
the first decryption information.