  Secure data deletion enables data owners to fully control the erasure of
their data stored on local or cloud data centers and is essential for
preventing data leakage, especially for cloud storage. However, traditional
data deletion based on unlinking, overwriting, and cryptographic key management
either ineffectiveness in cloud storage or rely on unpractical assumption. In
this paper, we present SevDel, a secure and verifiable data deletion scheme,
which leverages the zero-knowledge proof to achieve the verification of the
encryption of the outsourced data without retrieving the ciphertexts, while the
deletion of the encryption keys are guaranteed based on Intel SGX. SevDel
implements secure interfaces to perform data encryption and decryption for
secure cloud storage. It also utilizes smart contract to enforce the operations
of the cloud service provider to follow service level agreements with data
owners and the penalty over the service provider, who discloses the cloud data
on its servers. Evaluation on real-world workload demonstrates that SevDel
achieves efficient data deletion verification and maintain high bandwidth
savings.
