FHE Fundamentals

Fully Homomorphic Encryption (FHE) enables arbitrary computations to be performed directly on encrypted data without revealing the underlying plaintext. Unlike conventional encryption schemes, where data must be decrypted before processing, FHE preserves confidentiality throughout the entire computation lifecycle, making it a foundational technology for privacy-preserving computation.

Key concepts in FHE include homomorphic addition and multiplication, bootstrapping, ciphertext noise management, programmable bootstrapping, and modern lattice-based cryptographic assumptions such as Learning With Errors (LWE). These concepts form the basis of most contemporary FHE systems and applications.

For readers seeking a comprehensive introduction to FHE, including its mathematical foundations, historical evolution, major schemes, engineering challenges, and real-world applications, we recommend the Primus FHE101 tutorial:

https://fhe101.primuslabs.xyz/en/

Interested readers may refer to the FHE101 documentation for a detailed treatment of the subject.