Patent ID: 8677143

Claim:
A playing method of digital right managing (DRM) multimedia in which files of DRM multimedia to be played take a page as a basic playing unit, when operation of fast-forward/fast-reverse is triggered, the playing method comprising: determining a time duration of fast-forward/fast-reverse from a first page to a target page; determining a number of pages of fast-forward/fast-reverse based on the time duration of fast-forward/fast-reverse; determining a position of the target page based on the number of pages of fast-forward/fast-reverse; calculating a key stream of the position of the target page based on prestored key data of the first page without calculating a key of a page between the first page and the target page; decrypting ciphertext of the target page based on the calculated key stream of the position of the target page; and decoding the decrypted target page, and starting to play from the decrypted target page, wherein determining a number of pages of fast-forward/fast-reverse based on the time duration of fast-forward/fast-reverse includes determining a number n of pages of fast-forward/fast-reverse based on the time duration of fast-forward/fast-reverse by dividing the time duration of fast-forward/fast-reverse of n pages by a time duration of fast-forward/fast-reverse of a single page, and wherein calculating a key stream of the position of the target page includes calculating the key stream of the position of the target page according to the prestored key data of the first page and the position of the target page.