# Signing and Verifying Messages (/smart-accounts/sign-and-verify)

> For the complete documentation index, see [llms.txt](/llms.txt)



There are a few reasons why:

* With an EOA, the address is effectively the public key of the private key used for signing.  Therefore, verifying a EOA signature is as simple as [recovering](https://soliditydeveloper.com/ecrecover) the signature and compare the recovered public key with the address.
  * With a smart account, the address is the address of a smart contract that has no cryptographic link to the signing private key.  Therefore, you must use [ERC-1271](https://eips.ethereum.org/EIPS/eip-1271) to validate the message.

* With an EOA, you don't have to deploy the account.  It just exists.
  * Since smart accounts need to be deployed, it may not be clear how you can validate messages against a smart account not yet deployed.  However, that's actually possible thanks to [ERC-6492](https://eips.ethereum.org/EIPS/eip-6492).

If you are impatient, head straight to [the API](#api).  Otherwise, read on to learn more about ERC-1271 and ERC-6492.

## Understanding ERC-1271 and ERC-6492 [#understanding-erc-1271-and-erc-6492]

TODO

## API [#api]

### Signing messages [#signing-messages]

Both [the account and account client objects](/onboarding/create-a-smart-account#create-a-kernel-account) are able to sign messages:

```ts
const signature = await account.signMessage({
  message: 'hello world',
})

const signature = await kernelClient.signMessage({
  message: 'hello world',
})
```

If the account hasn't been deployed, a ERC-6492 signature will be generated.

### Validating signatures [#validating-signatures]

While you can validate signatures with ERC-1271, it's recommended that you use ERC-6492 since it works just like ERC-1271 if the account has been deployed, but it can also validate signatures for undeployed accounts.

To validate signatures with ERC-6492:

```ts
import { verifyEIP6492Signature } from '@zerodev/sdk'
import { hashMessage } from "viem"

await verifyEIP6492Signature({
  signer: account.address, // your smart account address
  hash: hashMessage('hello world'),
  signature: signature,
  client: publicClient,
})
```