8 min read
What FHE changes for on-chain apps
Fully homomorphic encryption lets you compute over data you never decrypt. Here is what that actually unlocks on a public ledger.
Public blockchains are public by construction, which rules out most applications where the amounts are the sensitive part. Fully homomorphic encryption changes the constraint: you can compute over encrypted values without decrypting them.
What becomes possible
- Private ledgers — balances and transfer amounts stay hidden while remaining computable.
- Blind auctions — bids are secret from other bidders and from the contract owner.
- Confidential voting — individual votes stay private while the tally stays verifiable.
The catch is performance
FHE is real, and it is slow. That is not a temporary problem to engineer around — it is the current shape of the technology, and it decides which use cases are viable.
Ledger state is a good fit: writes are infrequent, correctness matters more than latency, and the privacy is the entire point. Anything interactive is not, at least not yet.
Private Ledger Flow was my attempt to find where that line sits by building on Zama's FHEVM rather than reading about it. The line is further along than I expected, and still well short of where most demos imply.