Integrity verification using Identity based Provable Data Possession in multi storage cloud

In the cloud computing environment multi storage cloud technique has been popularly used by many organizations to mitigate disaster recovery and to increase the flexibility for the user. The data being outsourced by the client in a storage server may get corrupted. This leads to a threat to the integrity of the client's confidential data. We use a technique called Provable Data Possession (PDP) [1] using which we verify the integrity of the outsourced data in an untrusted server without retrieving the entire file from the cloud server or having a copy of the data. Identity Based Encryption (IBE) [5] and other PDP schemes are used for its implementation. To implement PDP (provable Data Possession) in verifying the integrity of the outsourced data we use HMAC (Hashed Message Authentication Code). A message digest is generated using HMAC with the combination of a secret key. A secret key is generated for the user identity by running a setup algorithm which performs Identity Based Encryption (IBE). One of the Cloud Service Provider (CSP) will act as a combiner. The proof generated by the Cloud service provider is verified by the client which will be acting as a verifier. The Cloud Service Provider is reported if the proof generated by the prover is wrong.