> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Blob.verify

> Verify KZG proof for blob and commitment

<Card title="Try it Live" icon="play" href="https://playground.tevm.sh?example=primitives/blob.ts">
  Run Blob examples in the interactive playground
</Card>

<Tabs>
  <Tab title="Standard API">
    ```typescript theme={null}
    import { Kzg, Blob } from 'tevm';

    const blob = Blob.fromData(data);
    const commitment = Kzg.Commitment(blob);
    const proof = Kzg.Proof(blob, commitment);

    const isValid = Kzg.verify(blob, commitment, proof);
    console.log(isValid); // true
    ```

    **Note:** Requires c-kzg-4844 library integration (coming soon).
  </Tab>

  <Tab title="Factory API">
    ## `Verify({ verifyBlobKzgProof })(blob, commitment, proof): boolean`

    Tree-shakeable factory pattern with explicit KZG dependency.

    **Dependencies:**

    * `verifyBlobKzgProof: (blob: Uint8Array, commitment: Uint8Array, proof: Uint8Array) => boolean` - KZG verification function from c-kzg-4844

    **Example:**

    ```typescript theme={null}
    import { Kzg } from 'tevm'
    import { verifyBlobKzgProof } from 'c-kzg'

    const verify = Kzg.VerifyFactory({ verifyBlobKzgProof })
    const isValid = verify(blob, commitment, proof)
    ```

    **Bundle size:** KZG crypto only included if you import it explicitly.

    **Note:** Requires c-kzg-4844 library integration (coming soon).
  </Tab>
</Tabs>

## Verification Process

KZG proof verification checks that blob data matches commitment:

```
1. Parse blob as polynomial coefficients (4096 field elements)
2. Evaluate polynomial at challenge point
3. Verify pairing equation: e(commitment, G2) = e(proof, challenge_G2)
```

### Why Verify?

```typescript theme={null}
import { Kzg } from 'tevm';

// Scenario: Received blob transaction from network
const receivedBlob = /* from network */;
const receivedCommitment = /* from transaction */;
const receivedProof = /* from transaction */;

// Verify without recomputing commitment (faster)
const isValid = Kzg.verify(receivedBlob, receivedCommitment, receivedProof);

if (!isValid) {
  throw new Error('Blob data does not match commitment');
}

// Can trust blob data matches what sender committed to
```

## Batch Verification

For multiple blobs, use `verifyBatch()` (more efficient):

```typescript theme={null}
import { Kzg } from 'tevm';

const blobs = [blob1, blob2, blob3];
const commitments = blobs.map(b => Kzg.Commitment(b));
const proofs = blobs.map(b => Kzg.Proof(b));

// Single batch verification (faster than 3 individual verifications)
const allValid = Kzg.verifyBatch(blobs, commitments, proofs);

if (!allValid) {
  // Fallback: find which blob failed
  for (let i = 0; i < blobs.length; i++) {
    if (!Kzg.verify(blobs[i], commitments[i], proofs[i])) {
      console.error(`Blob ${i} failed verification`);
    }
  }
}
```

## Security Properties

### Soundness

Cannot create valid proof for wrong blob:

```typescript theme={null}
import { Kzg, Blob } from 'tevm';

const blob1 = Blob.fromData(data1);
const commitment1 = Kzg.Commitment(blob1);
const proof1 = Kzg.Proof(blob1);

const blob2 = Blob.fromData(data2); // Different data

// Proof for blob1 doesn't work with blob2
console.log(Kzg.verify(blob1, commitment1, proof1)); // true
console.log(Kzg.verify(blob2, commitment1, proof1)); // false

// Cannot forge proof
const fakeProof = new Uint8Array(48);
console.log(Kzg.verify(blob1, commitment1, fakeProof)); // false
```

### Completeness

Valid proofs always verify:

```typescript theme={null}
import { Kzg, Blob } from 'tevm';

const blob = Blob.fromData(data);
const commitment = Kzg.Commitment(blob);
const proof = Kzg.Proof(blob);

// Always verifies for correctly generated proof
console.log(Kzg.verify(blob, commitment, proof)); // true (always)
```

## See Also

* [toCommitment](./toCommitment) - Generate commitment
* [toProof](./toProof) - Generate proof
* [verifyBatch](./verifyBatch) - Batch verification
* [KZG](/primitives/blob/kzg) - KZG commitment scheme details