In order to protect the confidentiality and privacy security of the composite documents within the whole life cycle

we leverage attribute-based encryption (ABE) algorithm to propose a secure self-destruction scheme for composite documents

referred to as SelfDoc.We firstly set up a new composite document structure by employing the idea of multilevel security

and then

use an access key to encrypt the composite document and the ABE algorithm to encrypt the access key.After a series of algorithms for extracting and transforming from the two ciphertexts

we obtain ciphertext shares and encapsulated self-destruction object

both of which are stored into two distributed hash table (DHT) networks and cloud servers respectively.Nodes in the DHT networks will self-discard the ciphertext shares periodically

so the original ciphertext and access key are unrecoverable after the expiration time

and the function of secure self-destruction is achieved.Compared with existing schemes

the security analyses indicate that SelfDoc scheme is able to resist the traditional cryptoanalysis or brute-force attack

and the Sybil attacks from the DHT networks.