A Secure Electronic Document Self-Destructing Scheme in Cloud Computing

The timed-released electronic documents stored in cloud servers for a long time become increasingly easy to leak privacy information to the Internet. To overcome this problem, we develop a novel two-step scheme for self-destructing electronic document by using identity-based timed-release encryption (ITE), referred to as ESITE. In the first step, we use symmetric key to encrypt the electronic document. Thus, we can obtain an extracted ciphertext and an encapsulated ciphertext by using an extraction algorithm. Secondly, we use ITE algorithm to encrypt the symmetric key. On one hand, we get the ciphertext shares and distribute it into the distributed Hash table (DHT) network by combining key’s ciphertext and the extracted ciphertext. On the other hand, the encapsulated ciphertext is stored in cloud servers after being encapsulated into a self-destructing object. There are two advantages for the proposed scheme. First, we can only access the protected electronic document when the desired release time arrived . Second, the original decryption key cannot be recovered after a certain period of time. The reason is that DHT network will discard the stored ciphertext shares automatically, so the function of self-destruction is implemented safely. Security analysis shows that the proposed ESITE scheme is able to resist against cryptanalysis attacks from the cloud servers and the Sybil attacks from the DHT network. Experimental results demonstrate that the computational overheads of the proposed scheme is much lower than existing schemes.