Data output method, system and apparatus

A data output method comprising the steps of:

• (a) encrypting a first data set, said encrypting being based on encryption parameters that comprise:
• i. public data of a trusted party, and
• ii. an encryption key string comprising a second data set that defines a policy for allowing the output of the first data set to a removable storage medium,
• (b) providing the encrypted first data set to an output device adapted to output data to a removable storage medium;
• (c) at the trusted party checking that said policy has been satisfied and thereafter providing the output device with a decryption key, distinct from the encryption key string, for use in decrypting the encrypted first data set, this decryption key being generated in dependence on the encryption key string and private data related to said public data;
• and
• (d) at the output device using the decryption key in decrypting the encrypted first data set and outputting the first data set to a removable recording medium.

A printing system comprising:

• a printer;
• a first computing entity for encrypting a first data set, the first computing entity encrypting the first data set based on encryption parameters that comprise:
• i. public data of a trusted party, and
• ii. an encryption key string comprising a second data set that defines a policy for allowing the printing of the first data set,
• the first computing entity being further arranged to output the encrypted first data set for the printer;
• and
• a second computing entity associated with the trusted party and arranged when satisfied that said policy has been met, to output for the printer a decryption key, distinct from the encryption key string, for use in decrypting the encrypted first data set, the second computing entity being arranged to generate this decryption key in dependence on the encryption key string and private data related to said public data;
• the printer being arranged to use the decryption key in decrypting the encrypted first data set.