Understanding Fully Homomorphic Encryption
Fully Homomorphic Encryption (FHE) is an encryption scheme that enables computations to be performed on encrypted data.
Its primary objective is to allow computations to be carried out on ciphertext without the need for decryption at any intermediate step of the computation.
Balancing Data Privacy and Large-Scale Processing
This capability holds great significance in use cases such as cloud computing and big data analytics, where large-scale data processing is required while maintaining the privacy of third-party sensitive or proprietary information.
At first glance, the concept may seem impossible.
How can operations like addition and multiplication be performed on encrypted data without decrypting it?
The challenge lies in traditional encryption schemes having separate keys for encryption and decryption, and performing operations on encrypted data necessitates decryption beforehand.
In the case of Fully Homomorphic Encryption (FHE), an encryption key is still used.
However, unlike traditional schemes, computations can be carried out on plaintext arbitrarily without the need for decryption.
The Utility of Homomorphic Encryption
Fully Homomorphic Encryption offers a valuable property by enabling computation on sensitive data without exposing it to the entity performing the computation.
Distinguishing Fully Homomorphic Encryption from Other Forms
Various types of homomorphic encryption exist regarding the feasibility of computations on encrypted data, including partially homomorphic, somewhat homomorphic, leveled fully homomorphic, and fully homomorphic encryption.
Partially homomorphic and somewhat homomorphic encryption only support specific types of operations on encrypted data, and their usage may be limited in terms of repetition.
On the other hand, Fully Homomorphic Encryption allows for an unlimited number of operations on encrypted data, without any constraints on the type or frequency of the operations.
Benefits of Fully Homomorphic Encryption
FHE enables the storage of sensitive private data on third-party servers while facilitating computation on that encrypted data while maintaining its privacy.
Server administrators cannot ascertain the nature of the computations performed on the private data (assuming a secure FHE implementation).
FHE eliminates the tradeoff between data usability and privacy, preserving data privacy without the need to mask or remove any features.
A properly implemented FHE scheme provides resilience against quantum attacks, making it quantum-safe.
Although FHE is still an emerging field and currently considered commercially infeasible, extensive research is underway to enhance its usability in the future.