A giant RTX graphics card with two fans standing on a grassy hill under a low bank of cumulus clouds, cables running to a person in a yellow hoodie working on a laptop.

Private RTX 5090 hours, shielded on Zcash.

[ devnet: free test vouchers, fees waived, no GPU starts yet ]

01 / the voucher

One voucher is one hour on an RTX 5090.

NVIDIA GeForce RTX 5090: 32 GB of GDDR7 and 21,760 CUDA cores, the card people rent by the hour for inference and fine-tuning.

02 / held privately

Your hours sit in a shielded Zcash wallet.

Vouchers are a Zcash Shielded Asset. Moving them between people shows up on chain as a transaction with no amount, no asset and no addresses.

03 / spent when you like

Redeem them for a session, whenever.

Send hours back to the provider and get a session key. Only the provider learns how many. On this devnet the session is recorded, no GPU starts yet.

01 / 05
Issue
[ public on chain ]
The provider mints a million RTX 5090 hours in the open. Anyone can count how many exist.
02 / 05
Claim
[ shielded on chain ]
Hours move from the provider into your wallet. The chain records a shielded transaction and nothing else.
03 / 05
Trade
[ shielded on chain ]
Sell or gift hours to anyone with a zhour address. No amount, no asset and no addresses reach the chain.
04 / 05
Redeem
[ shielded on chain ]
Send hours back and get a session. Only the provider learns how many, and the devnet only records the credit.
05 / 05
Burn
[ public on chain ]
Redeemed hours are burned in batches, so no public burn lines up with one person's usage.

Everyone sees fog.

A grassland planted with rows of identical RTX cards, all veiled in thick white fog.

Transfers between people land in the shielded pool with no amount, no asset and no addresses. Your viewing key is the only thing that finds your hours in it.

A person in a yellow raincoat on a ridge at golden hour holding up a glowing ticket, a giant RTX card on a distant hill.

Hold the hours.

It lives in this tab. The recovery phrase and every proof stay in your browser.

Loading the proving engine…

Anyone can count them.

Live from the devnet. Issuance and burns are public, so the supply is always checkable. Everything between people is a striped square.

…

[ RTX 5090 hours in existence ]

Issued by the provider: …
Burned after redemption: …
Redeemed, waiting for the next burn: …

Reading the chain…

Shielded transfer: amount, asset and addresses hiddenIssuance, publicBurn, public

What is real today.

Every moving part, with live numbers, is on how zhour works.

Network: zhour's own Zcash devnet, on QEDIT's ZSA build of Zebra. Zcash Shielded Assets are not on mainnet: the NU7 upgrade left them out, and the public ZSA testnet does not accept outside blocks right now.
Voucher: A Zcash Shielded Asset (ZIPs 226 and 227) named zhour:RTX-5090-GPU-hour. One voucher is one hour on an NVIDIA GeForce RTX 5090. A million were issued in public.
Price: Free on the devnet: 25 hours per claim, three claims per address. On a live service this is where you would pay.
Fees: Waived on this devnet. On a real network every transaction pays a small ZEC fee, so holders would need a little ZEC as well.
Proving: In your browser, on as many threads as it gets. The service only ever receives signed transactions.
Redemption: Credits a session record for the hours you sent back. No GPU starts yet.
Burns: In batches, at 50 hours or after three minutes. Batching only hides one person's usage when several people redeem in the same batch.

Private RTX 5090 hours, shielded on Zcash.

The card behind every voucher

How it works

Everyone sees fog.

Hold the hours.

Anyone can count them.

What is real today.