Abstract: Assured deletion of cloud data is a key issue to be solved in the field of cloud storage secu- rity. Existing schemes generally have the drawbacks of over-reliance on key destruction, lack of strong non-separability of ciphertext, excessive encryption and decryption overhead and so on. To solve these problems, by combining AONT conversion with block cipher, a cloud data assured deletion scheme is proposed, which achieves strong non-separability of ciphertext by confusing the original data itself. Theoretical analysis and experimental results show that destroying any piece of cipher data will result in unrecoverable original data in this scheme, thus getting rid of over-reliance on key destruction, which achieves the expected goal of trusted deletion. At the same time, by introducing data block shuffling and reducing the number of cryptographic operations, the ability of anti-ciphertext analysis is improved and the computing overhead is significantly reduced. This scheme has obvious performance advantages compared with existing schemes.

Key words: cloud storage, cloud security, assured deletion, trusted deletion, strongly non-separable, data erasure