Compact Stateful Encryption Schemes with Ciphertext Verifiability
Increasingly wider deployment of encryption schemes call for schemes possessing additional properties such as randomness re-use, compactness and ciphertext verifiability. While novel approaches such as stateful encryption schemes contributes for randomness re-use (to save computational efforts), the requirements such as ciphertext verifiability leads to increase in the size of ciphertext. Thus, it is interesting and challenging to design stateful encryption schemes that offer ciphertext verifiability and result in compact ciphertexts. We propose two new stateful public key encryption schemes with ciphertext verifiability. Our schemes offer more compact ciphertexts when compared to all existing stateful public key encryption schemes with ciphertext verifiability. Our first scheme is based on the SDH assumption and the second scheme is based on the CDH assumption. We have proved both the schemes in the random oracle model.
KeywordsStateful Public Key Encryption Adaptive Chosen Ciphertext Security (CCA) Compact Ciphertext with Ciphertext Verification Random Oracle model
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