Paper 2021/331

A Probabilistic Public Key Encryption Switching Protocol for Secure Cloud Storage Applications

Radhakrishna Bhat, N R Sunitha, and S S Iyengar


The high demand for customer-centric applications such as secure cloud storage laid the foundation for the development of user-centric security protocols with multiple security features in recent years. But, the current state-of-art techniques primarily emphasized only one type of security feature i.e., either homomorphism or non-malleability. In order to fill this gap and provide a common platform for both homomorphic and non-malleable cloud applications, we have introduced a new public key based probabilistic encryption switching (i.e., homomorphism to/from non-malleability property switching during the encryption phase without changing the underlying security structure) scheme by introducing a novel Contiguous Chain Bit Pair Encryption (CC-BPE) and Discrete Chain Bit Pair Encryption (DC-BPE) techniques for plaintext bits encryption and using quadratic residuosity based trapdoor function of Freeman et al. [13] for intermediate ciphertext connections. The proposed scheme generates O ( m +2 log N ) bits of ciphertext where m &#8712; N and m < n , n &#8712; N is the plaintext size, N is the RSA composite. This security extension would be helpful to cover both homomorphism and non-malleability cloud applications. The superior performance of the proposed scheme has been tested in comparison to existing methods and is reported in this paper.

Available format(s)
Public-key cryptography
Publication info
Preprint. MINOR revision.
Probabilistic encryptionpublic key cryptosystemquadratic residuosity assumptionencryption switching protocolhomomorphic encryptionnon-malleabilitysecure cloud storage and retrieval
Contact author(s)
rsb567 @ gmail com
2022-02-09: revised
2021-03-14: received
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Creative Commons Attribution


      author = {Radhakrishna Bhat and N R Sunitha and S S Iyengar},
      title = {A Probabilistic Public Key Encryption Switching Protocol for Secure Cloud Storage Applications},
      howpublished = {Cryptology ePrint Archive, Paper 2021/331},
      year = {2021},
      note = {\url{}},
      url = {}
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