Hybrid Encryption Combines Classic and Post-Quantum Crypto for Future-Proof Security

Hybrid encryption addresses a core tension in modern cryptography by pairing battle-tested classical algorithms, such as X25519 and Ed25519, with newer post-quantum standards like ML-KEM-1024 and ML-DSA-87. The approach ensures a system remains secure unless both algorithms are broken simultaneously, making it resilient against both classical and quantum attackers. Key exchange and digital signatures each use an AND-combination model, where both algorithm outputs must succeed for the operation to be valid. An open-source library called Quipu implements this hybrid model for data at rest, operating at NIST Security Level 5 under the CNSA 2.0 framework. However, Quipu's composition of these primitives has not yet undergone an independent cryptographic audit, which experts recommend before deploying it for high-value sensitive data.