# OP\_CHECKMULTISIGVERIFY

<figure><img src="/files/C98gBrKwbH8sl0eBbYcy" alt=""><figcaption></figcaption></figure>

**OP\_CHECKMULTISIGVERIFY** performs an ECDSA signature check consuming up to i items from the stack, where n is the number of public keys in the group, m is the number of signatures needed and i = n + m + 3. If the multisignature condition is valid, the script continues to process.

| **Word**                | **Hex** | **Input**                               | **Output**     | **Description**                                                                          |
| ----------------------- | ------- | --------------------------------------- | -------------- | ---------------------------------------------------------------------------------------- |
| OP\_CHECKMULTISIGVERIFY | 0xaf    | x sig1 sig2 ... \<n> pub1 pub2 ... \<m> | Nothing / fail | Same as OP\_CHECKMULTISIG, but runs OP\_VERIFY afterward. Fails if multisig check fails. |

**Example:**

```
OP_0 <signature_1> <signature_3> OP_2 <public_key_1> <public_key_2> <public_key_3> OP_3 OP_CHECKMULTISIGVERIFY
```

*Note: The first item pushed using OP\_0 is called the junk item, required due to an off-by-one bug in the original implementation.*

In this example, n = 2 and m = 3 so there are 2(signatures) + 3(pubkeys) + 2(indicators) + 1(junk item) = 8 items consumed from the stack. To spend an output with this multisignature script, the user must submit a junk item and 2 valid signatures corresponding to 2 of the public keys in the list, in the correct order.


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