Quantum Computers, The Day They Swallow Passwords is Coming..."Calculations Completed Without Decryption"

▲ Quantum Computer/AI Generated Image

As the era approaches where quantum computers target the weaknesses of existing cryptographic systems, Fully Homomorphic Encryption (FHE) is emerging as a key alternative for blockchain privacy protection and post-quantum cryptography.

According to crypto media outlet U.Today on May 26 (local time), most currently widely used encryption technologies are based on the premise that factoring very large numbers is difficult. RSA, Diffie-Hellman, and Elliptic Curve Cryptography all rely on the same assumption, but this premise could collapse if a sufficiently powerful quantum computer is combined with Shor's Algorithm. U.Today reported that attackers are already employing a 'collect now, decrypt later' strategy, gathering encrypted traffic now and planning to decrypt it with quantum computers in the future.

The U.S. National Institute of Standards and Technology (NIST) formalized this sense of crisis by announcing the first three post-quantum cryptography standards in August 2024. All three standards are based on lattice-based mathematics and belong to a class of problems that are difficult for quantum computers to directly break, even with increased speed. Fully Homomorphic Encryption (FHE) also falls into the same category. FHE's security is based on the Learning With Errors (LWE) problem, which involves hiding a secret vector within a high-dimensional lattice and concealing it with carefully added noise.

The core of FHE is its ability to perform computations without decrypting the data. Conventional encryption protects data at rest and data in transit, but to query, compute, or execute logic, the data must be decrypted at least once. FHE performs arbitrary computations on encrypted data and then returns an encrypted result. Neither the server performing the computation nor any third party observing the network can see the original data, and the result can only be decrypted by the entity holding the private key.

U.Today explained that this technology directly addresses the transparency issues of blockchain. Public blockchains are designed so that anyone can verify transactions, wallet balances, and smart contract states, but this can be a vulnerability from the perspective of financial privacy, protecting trading strategies, and regulatory compliance. Zero-Knowledge Proofs demonstrate that a computation has been performed correctly without revealing input values, but they do not allow for continuous and interactive computations on encrypted data. FHE offers differentiation in use cases where data must remain encrypted, such as sealed-bid auctions, private voting, confidential loans, and on-chain medical records.

Fhenix is building an FHE infrastructure layer for Ethereum (ETH) and EVM-compatible chains. Its core product is an Ethereum-compatible environment where smart contracts can natively process encrypted data. Fhenix designed its architecture around the CoFHE coprocessor, which offloads heavy cryptographic operations off-chain while maintaining privacy and EVM compatibility. The company has deployed CoFHE in a live environment on Arbitrum and launched a Helium public testnet in mid-2024. An example was also presented where a single developer built a fully private voting application on the Fhenix devnet within 24 hours.

Fhenix attracted strategic investment from BIPROGY, a major Japanese IT service company, in October 2025. U.Today evaluated this investment as a sign that on-chain confidentiality is no longer a speculative slogan but is close enough to a production environment to be considered at the financial infrastructure level. The immediate value of FHE lies in its ability to perform computations without exposing sensitive data to validators, cloud providers, or attackers monitoring the chain, and its quantum resistance stems from its inherent structure, not a separate feature.

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