Add to ORKGInternational audienceSomewhat Homomorphic Encryption (SHE) schemes can be used to carry out operations on ciphered data. In a cloud computing scenario, personal information can be processed secretly, inferring a high level of confidentiality. The principle limitation of SHE is the size of ciphertext compared to the size of the message. This issue can be addressed by using a batching technique that “packs” several messages into one ciphertext. However, this method leads to important drawbacks in standard implementations. This paper presents a fast hardware/software co-design implementation of an encryption procedure using the Karatsuba algorithm. Our hardware accelerator is 1.5 times faster than the state of the art for 1 encryption and 4 t...