Patent ID: 7493662

Claim:
A computing device comprising: a recording medium operable to record target data, the target data being made up of a plurality of data blocks; a reproducing unit operable to reproduce the target data from the recording medium; a first judging unit operable to judge, for each data block recorded on the recording medium, whether the data block needs to be nullified when the data block is reproduced from the recording medium; a sequential nullifying unit operable to destroy only a part of the reproduced data block judged as needing to be nullified while the reproducing unit reproduces the target data from the recording medium, the part of the reproduced data block including data necessary to reproduce remaining parts of the reproduced data block judged as needing to be nullified, the remaining parts being unable to be reproduced without the part of the reproduced data block judged as needing to be nullified; a total nullifying unit operable to destroy all of the remaining parts that have not been destroyed by the sequential nullifying unit; and a processing capacity judging unit operable to judge whether the computing device has a processing capacity sufficient to destroy all of the remaining parts while the reproducing unit reproduces the target data from the recording medium, and to control the total nullifying unit to destroy all of the remaining parts when the processing capacity judging unit judges that the computing device has the processing capacity sufficient to destroy all of the remaining parts.