# Verification Methods

A vBase stamp proves that your file or content existed on or before the date/time it was recorded on a public blockchain. Stamp verification requires you only to possess a copy of the underlying content/file.

## Why This Matters

Traditional approaches to proving authenticity depend on **centralized databases** or **storing receipts** that can be lost, altered, or disputed.

With vBase:

* Verification is **independent** — anyone can check a file against the blockchain.
* There’s **no single point of trust** (no company-controlled registry you must rely on).
* There’s **no need to keep track of certificates or receipts** — the blockchain record itself is the proof.

This makes vBase the only tool that delivers **reliable, permanent verification of content authenticity** without relying on an intermediary.

## Quick Reference

| Method   | Category      | Input Needed                  | Where to Verify                                                             |
| -------- | ------------- | ----------------------------- | --------------------------------------------------------------------------- |
| Method 1 | With vBase    | Original file                 | [vBase Verify](https://app.vbase.com/verify)                                |
| Method 2 | With vBase    | ContentID (hash)              | `https://app.vbase.com/verify?cid=<ContentID>`                              |
| Method 3 | Without vBase | SHA3-256 hash                 | [Dune dashboard](https://dune.com/vbase/stamp-search)                       |
| Method 4 | Without vBase | Transaction ID                | [PolygonScan](https://polygonscan.com/)                                     |
| Method 5 | Without vBase | ContentID, address, timestamp | vBase Smart contract                                                        |
| Method 6 | vBase API     | ContentID (hash)              | [REST API docs](https://docs.vbase.com/getting-started/rest-api-user-guide) |
| Method 7 | vBase API     | ContentID (hash)              | [Python SDK docs](https://docs.vbase.com/python-sdk/index)                  |

## What You’ll Need

* The **original file** that was stamped
* The **hashing algorithm** used. By default vBase uses `SHA3-256`

## With vBase Tools

### Method 1: vBase Verify (Recommended)

1. Go to [app.vbase.com/verify](https://app.vbase.com/verify).
2. Upload your file.
3. vBase computes the SHA3-256 hash and checks it against the blockchain record.
4. If a matching stamp is found, you’ll see:
   * The **timestamp (UTC)**
   * The **transaction ID**
   * The **blockchain address**

### Method 2: Verify via ContentID

1. Compute your file’s SHA3-256 hash using any hashing tool (e.g., [emn178 SHA3-256 tool](https://emn178.github.io/online-tools/sha3_256_checksum.html)) or using the OpenSSL library.
2. Copy the **ContentID (hash)** and append it to the verify URL:

   ```
   https://app.vbase.com/verify?cid=<ContentID>
   ```

## Without vBase Tools

### Method 3: Dune Dashboard

1. Compute your file’s SHA3-256 hash using any hashing tool (e.g., [emn178 SHA3-256 tool](https://emn178.github.io/online-tools/sha3_256_checksum.html)).
2. Input the hash into the [vBase Dune dashboard](https://dune.com/vbase/stamp-search).
3. Confirm that the returned record matches your certificate details (timestamp, submitter address).

### Method 4: Blockchain Explorer

1. Use the **Transaction ID** from your stamping transaction.
2. Open [PolygonScan](https://polygonscan.com/) and input this transaction id.
3. Locate the data hash embedded in the transaction input.
4. Compare the published against the hash of your content.

### Method 5: Smart Contract Validation

1. Identify the vBase smart contract on **Polygon Mainnet (Chain ID: 137)**:\
   [0x80D2AB15EE5b91cD7A183b8938dC277fE6191F7d](https://polygonscan.com/address/0x80D2AB15EE5b91cD7A183b8938dC277fE6191F7d)
2. Call the validation function with:

   ```
   validate(cid, user_address, timestamp)
   ```

   * `cid`: your file’s ContentID (hash)
   * `user_address`: the stamper's blockchain address
   * `timestamp`: the timestamp (in blocks) for the stamp (note, timestamp can be approximate and you can iterate over many timestamps)
3. Verify that the function returns `true`.

## API Methods

### Method 6: vBase REST API

* Use the vBase REST API to query a stamp by its ContentID.
* See the [REST API documentation](https://docs.vbase.com/getting-started/rest-api-user-guide) for endpoint details, authentication, and response formats.

### Method 7: vBase Python SDK

* Install the vBase Python SDK and call the built-in verification function with a ContentID.
* See the [Python SDK documentation](https://docs.vbase.com/python-sdk/index) for usage examples.

## Notes on Validation

* **If a stamp is found:** Your file existed on or before the recorded timestamp.
* **If no stamp is found:** No blockchain record exists for that file.
* **Privacy:** Only the cryptographic fingerprint (hash) is stored on-chain. File contents are never exposed.