The short version of how a file is stored in CT3 is familiar to most users: upload the file, choose a storage period, pay for it, and receive an NFT key in your wallet that can be passed on to someone else. The description is accurate, and it leaves out almost everything that makes the model work.

This article covers the full path of a file, from the moment it leaves your device to the moment the access key appears in your wallet. It also covers what each step means in practice when you store, renew, transfer or delete data. Alongside the article we are publishing a short video guide in five languages.

The video explains how files are uploaded, encrypted, distributed across decentralized storage infrastructure, and made available to users when needed. It also gives a visual introduction to the core principles behind CT3 Cloud, including data protection, decentralized storage, and reliable access.

Watch the guide in your language:

‍English · German · Spanish · Italian · French

What You Need Before You Start

A Web3 wallet with access to the Polygon network: Backpack, MetaMask, Trust Wallet, Rabby, Coinbase Wallet or any other EVM-compatible wallet. Payment is made in POL.

No registration, no KYC procedure and no bank card are required. The wallet acts as the account.

User-Side Steps, One by One

1. Open ct-3.cloud and connect your wallet.
2. Select a file and a storage period. The platform calculates the price for that volume and that period.
3. Pay for storage. At this step you can specify a separate recipient address for the NFT key, so that the key is minted to a wallet other than the one the payment came from.
4. Upload the file. Encryption, fragmentation and distribution across miner nodes begin during the upload, not after it completes.
5. Receive the NFT key on the paying wallet or on the recipient address you specified.

If the connection drops while a large file is uploading, the transfer can be resumed from the point where it stopped, within 48 hours of the moment the upload was initiated. Chunks already accepted by the network are held in a buffer for that entire window, so an interrupted session does not mean starting over.

How Pricing Works

The cost of storage is calculated from current network and miner load, together with the volume and period you select. You pay for the space you actually occupy, billed daily. There are no subscriptions, no fixed plans and no payment for unused capacity.

If a file is no longer needed, you delete it and receive a refund for the remaining unused days to the connected wallet. The storage period can be extended at any moment through the Renewal function. If the period expires and has not been extended, the file is deleted permanently, so it is reasonable to choose a period with a margin rather than at the lower bound.

What Happens to the File After You Press Upload

The file is encrypted on the client side with AES-256 before it leaves your device. Nothing readable is ever transmitted to the network.

The encrypted file is then processed through Erasure Coding and split into independent 5 MB chunks, uploaded in several parallel streams. Each chunk is indexed and receives its own hash. Miners retrieve their chunks by that hash and store them on their nodes.

After receiving the chunks, a miner generates a unique storage ID and uses the Proof of Replication protocol to confirm that the data is stored correctly. Throughout the storage period, the verification mechanism regularly checks that the miner still holds the file and is able to serve it on request. Miners that pass verification are rewarded. Miners that fail it are penalized through slashing.

Double Replication and Parity Data

User files are stored with double replication, meaning every file exists in at least two copies on different nodes. Erasure Coding adds a second layer: parity data makes it possible to reconstruct the file even when some chunks are lost, as long as the recovery threshold is met.

The same fragmentation that provides fault tolerance also provides confidentiality. No single node holds enough material to reconstruct anything, and what a miner physically holds is an encrypted fragment and a hash. The availability of your data does not depend on the availability of any particular operator.

The Integrity Anchor On-Chain

A cryptographic hash of the file and its metadata is written to the blockchain. That record serves as the reference point for integrity checks: if the stored content changes in any way, hash verification stops matching.

This is what makes it possible to verify a claim about data integrity instead of believing it. Trust becomes verification, not reliance.

How the NFT Key Works

Once the upload is complete and the chunks are distributed among miners, the NFT key is minted to the wallet that paid for storage, or to the recipient address specified at payment.

The key is issued under the ERC-721 standard on Polygon and carries file data in its attributes: name, size and storage period. A user key is linked to exactly one file in CT3 storage.

Several practical consequences follow from that link:

• Owning the key equals owning the file. Transferring or selling the key transfers access, and the new holder only needs to connect their wallet to CT3.
• Access is confirmed cryptographically. The holder signs a challenge message with their wallet, and ownership of the key is verified on-chain. CT3 keeps no internal user databases, since the blockchain is the source of truth.
• Burning the key through ct-3.cloud deletes the file and refunds the unused portion of the period.
• The full ownership history remains publicly verifiable on PolygonScan and OpenSea.

Downloading a File

To retrieve your data, connect the wallet holding the key and sign the challenge. Chunks are requested from several nodes at once and reassembled into the original file, which is decrypted on the client side. Only the key holder can decrypt it. If some nodes are unavailable at that moment, the gap is covered by parity data.

Practical Notes

The mechanics above come down to a few rules worth keeping in mind from your first upload.

• Choose a storage period with a margin. Renewal is available at any time, but a file whose period has expired cannot be recovered.
• The wallet holding the key is the point of access. Standard wallet hygiene applies here, and a lost wallet means a lost file.
• Transfer a file through the key, not through a second upload. Re-uploading creates a second file, a second payment and a second key.
• If you used a separate recipient address, maintain that separation afterwards. The point of splitting the payment address and the mint address is lost if you link them later.
• CT3 support never asks for passwords or seed phrases and never requests transfers. Check any link through ct-3.ltd.

All five points follow from a single property of the system. The file has no administrator, the access has no intermediary, and the key has only an owner. Client-side encryption, distributed chunks, the hash on-chain and the NFT key work together for exactly that: responsibility for the data passes fully to its owner, along with full control over it.

Follow CT3 across our official channels to stay up to date on platform updates, new features, and enterprise milestones:

• Official website: ct-3.ltd
• Official storage website: ct-3.cloud
• Support (Telegram): t.me/ct3_support_bot
• Email: contact@ct-3.ltd
• LinkedIn: linkedin.com/company/ct-3-secure-storage
• X (Twitter): x.com/ct3_io

If you discover any suspicious resources, fake accounts, or receive questionable offers, please report them immediately to our official support service.

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