SECURITY SCHEME FOR MOBILE DEVICES

摘要

At a content provider providing content for broadcast to a plurality of mobile devices, a method for distributing keys for decrypting content, the method including providing a plurality of encrypted decryption keys, the encrypted decryption keys being encrypted according to fSMK(gPK(CEK)), where f and g are encryption functions, fSMK is an encryption function encrypting gPK(CEK) according to a key, SKM, gPK(CEK) is an encryption function encrypting CEK according to a key PK, and CEK is a content encryption key enabling decryption of the content for a single crypto-period, transmitting the plurality of encrypted decryption keys to the plurality of mobile devices, and at an appropriate time relative to broadcast of the content encrypted according to key CEK, transmitting the key SKM to the plurality of mobile devices, thereby enabling the plurality of mobile devices to decrypt fSMK(gPK(CEK)) and derive gPK (CEK). Related apparatus and methods are described.