data value it is not necessary for a first generation device to verify that record length is sufficient to index into the encrypted key data first generation devices are assured that the encrypted key data contains a value corresponding to their device key 39 s associated row value referring now to fig6 a conditionally calculate variant data record format is shown according to an embodiment of the present invention a properly formatted skb may have zero or more conditionally calculate media key records bytes 4 through 19 of the record contain encrypted conditional data d ce if decrypted successfully as described below bytes 4 through 7 contain the value deadbeef 16 bytes 8 9 contains the associated column value for the device key to be used with this record and bytes 10 11 contain a generation value of 0001 16 for the first generation bytes 20 and higher contain doubly encrypted variant data possibly followed by some padding bytes at the end of the record not shown in fig6 the first ten bytes of the doubly encrypted key data correspond to sequence key row 0 the next ten bytes correspond to sequence key row 1 and so forth upon encountering a conditional calculate variant data record the device first calculates its current media key variant as follows k mv aes_ g k m d v u2225 0000000000000 16 where d v is its current variant data calculated from a previous calculate variant data record or conditional calculate variant data record using its current k mv value the device calculates conditional data d c as d c aes_ ecbd k mv d ce before continuing to process the.