The rapid development of the Internet of Things has made the issue of privacy protection even more concerning. Privacy protection has affected the large-scale application of the Internet of Things. Fully Homomorphic Encryption (FHE) is a newly emerging public key encryption scheme, which can be used to prevent information leakage. It allows performing arbitrary algebraic operations on data which are encrypted, such that the operation performed on the ciphertext is directly transformed into the corresponding plaintext. Recently, overwhelming majority of FHE schemes are confined to single-bit encryption, whereas how to achieve a multibit FHE scheme is still an open problem. This problem is partially (rather than fully) solved by Hiromasa-Abe-Okamoto (PKC′15), who proposed a packed message FHE scheme which only supports decryption in a bit-by-bit manner. Followed by that, Li-Ma-Morais-Du (Inscrypt′16) proposed a multibit FHE scheme which can decrypt the ciphertext at one time, but their scheme is based on dual LWE assumption. Armed with the abovementioned two schemes, in this paper, we propose an efficient packed message FHE that supports the decryption in two ways: single-bit decryption and one-time decryption.

中文翻译：

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实现消息封装的分级FHE以实现IoT隐私保护

物联网的飞速发展使隐私保护问题更加令人关注。隐私保护影响了物联网的大规模应用。完全同态加密（FHE）是一种新兴的公钥加密方案，可用于防止信息泄漏。它允许对加密的数据执行任意代数运算，从而将对密文执行的运算直接转换为相应的明文。最近，绝大多数的FHE方案都局限于单比特加密，而如何实现多比特FHE方案仍然是一个未解决的问题。Hiromasa-Abe-Okamoto（PKC'15）部分（而非完全）解决了这个问题，他提出了仅支持逐位解密的打包消息FHE方案。随后，In-crypt'16的Li-Ma-Morais-Du提出了一种多位FHE方案，该方案可以一次解密密文，但是它们的方案基于双重LWE假设。结合上述两种方案，本文提出了一种高效的打包消息FHE，它以两种方式支持解密：单位解密和一次性解密。