Zero-knowledge proofs meet mobile money

Understand exactly how KalyRails secures your transactions — from your user's phone to permanent settlement on KalyChain.

What is a ZK rollup — in plain English?

A ZK rollup is like having a notary who can stamp thousands of documents at once, proving they're all valid — without reading any of them aloud.

Your transactions happen on a fast, private chain. Periodically, a mathematical proof is generated that guarantees every transaction was valid. That proof is posted to KalyChain — a single, compact proof covering thousands of transactions.

The result: you get the speed and privacy of a private database with the security and auditability of a public blockchain. The best of both worlds.

Key properties

Private — transaction details stay on your chain, not visible publicly
Provably correct — math guarantees no invalid transactions can slip through
Immutable — once settled on KalyChain, records can never be altered
Fast — ~1s L2 confirmation, minutes to L1 settlement on KalyChain

Your transaction data never leaves your chain

KalyRails deploys every customer chain in validium mode. That's a crucial distinction from a standard ZK rollup, and it's the single biggest privacy guarantee we offer.

In a standard rollup, every transaction's compressed data is published to the public L1 — anyone in the world can inspect it, forever. In validium mode, only the cryptographic proof and state root are posted to KalyChain. The actual transaction data (amounts, user IDs, timestamps) stays off the public L1 entirely, held by you and your KalyRails infrastructure.

You get the full mathematical certainty of ZK proof verification — every batch is provably valid — without exposing a single customer transaction to public view. Regulators get audit access through your dedicated block explorer. Your competitors see nothing.

Validium vs standard rollup

STANDARD ROLLUP
Posts compressed transaction data to public L1. Anyone can reconstruct every transfer.
KALYRAILS VALIDIUM
Posts only the proof and state root to KalyChain. Transaction data stays with you — auditable privately by regulators, invisible to everyone else.
Same cryptographic security. Greater data sovereignty.

How a mobile money transaction flows through KalyRails

User sends money Via your mobile app Your backend JSON-RPC call ZK CHAIN Sequencer executes ~1s L2 confirmation Batcher creates batch ZK Prover Generates validity proof KALYCHAIN L1 Proof verified on-chain Immutable settlement Costs KLC gas Block explorer Audit trail for regulators USER LAYER No wallets needed MANAGED BY US You never touch infra SETTLEMENT LAYER Permanent, tamper-proof

How users transact without blockchain wallets

Traditional blockchain requires every user to manage a wallet — private keys, seed phrases, gas tokens. That's a non-starter for mobile money users who might be on a feature phone with a USSD interface.

KalyRails uses a custodial operator model. Your backend holds one signing key and submits every transaction from a single operator wallet. From the user's perspective, nothing changes — they tap "send" in your app, and the money moves.

Behind the scenes, the mobile money smart contract tracks balances as an internal mapping keyed by your existing user IDs. There are no per-user wallets, no per-user addresses, and no per-user gas. Your backend simply calls transfer(fromUserId, toUserId, amount) and the contract handles the rest.

USER SEES
Send $5 to Mamadou
Tap button → done
YOUR BACKEND DOES
Calls transfer(fromId, toId, amount)
Signs with one operator key
Submits to ZK chain RPC
ON-CHAIN RESULT
Immutable transfer record
Settled via ZK proof on KalyChain

What we run so you don't have to

Every KalyRails deployment includes a complete blockchain infrastructure stack, fully managed and monitored by our team.

Sequencer

Executes transactions, serves the JSON-RPC API your backend talks to, and batches transactions for proving. The core engine of your private chain.

ZK Prover

GPU-accelerated proof generation using the Boojum prover. Produces cryptographic validity proofs that mathematically guarantee every transaction in a batch was valid.

Block explorer

A dedicated explorer for your chain — indexer, API, and web interface. Your compliance team and regulators can verify any transaction at any time.

Database

Managed PostgreSQL with encryption, automated backups, and disaster recovery. Stores your chain's state and explorer data securely.

KUSD fee treasury

Per-transaction fees collected in KUSD at the smart contract layer flow to a dedicated treasury address — withdrawable to KalyChain L1 through the native token vault whenever you need to reconcile revenue.

L1 operator wallet

A funded KLC wallet on KalyChain that pays for batch commit and proof-verification transactions on L1. Managed and topped up by the KalyRails operations team.

Security through mathematics, not trust

ZK validity proofs

Unlike optimistic rollups that assume transactions are valid and rely on a 7-day challenge window, ZK rollups prove correctness upfront. Every batch is mathematically verified before settlement. There is no window for fraud.

Open-source stack

KalyRails is built entirely on ZKsync's open-source ZK Stack. The codebase has undergone $10M+ in security audits, 35+ external audits, and runs a bug bounty program paying up to $1.1M. This is battle-tested code.

Private by design

Your chain is permissioned — only your backend submits transactions. Transaction details are not visible on any public blockchain. Only compact ZK proofs are posted to KalyChain for verification.

Tamper-proof settlement

Once a proof is verified on KalyChain, the transaction record is permanent and cannot be altered by anyone — not by us, not by you, not by a bad actor. The math makes it impossible.

Ready to see the technology in action?

See how to connect your existing backend to a KalyRails ZK chain.

Integration guide Request a demo