# Verify Signature OffChain

The "Verify Signature OffChain" capability in the KrypC wallet-dev Service API enables users to verify the authenticity of cryptographic signatures associated with transactions or messages off-chain. This feature enhances security by allowing users to confirm the validity of signatures without interacting directly with the blockchain, facilitating trust and integrity in decentralized systems.

This will allow to Verify Signature off chain. 

## API Specification

## Verify Signature OffChain API

<mark style="color:green;">`POST`</mark> `https://api.krypcore.com/api/v0/devWallet/verifySignatureOffChain`

To verify signature offchain API under the given instance.&#x20;

#### Headers

| Name                                            | Type   | Description            |
| ----------------------------------------------- | ------ | ---------------------- |
| DappId<mark style="color:red;">\*</mark>        | String | DappId                 |
| Authorization<mark style="color:red;">\*</mark> | String | User Auth key obtained |
| SubscriptionId                                  | String | SubscriptionId         |
| ChainId                                         | String | ChainId                |

#### Request Body

| Name                                         | Type   | Description |
| -------------------------------------------- | ------ | ----------- |
| privateKey<mark style="color:red;">\*</mark> | String | Private Key |
| message<mark style="color:red;">\*</mark>    | String | Message     |
| signature<mark style="color:red;">\*</mark>  | String | Signature   |

{% tabs %}
{% tab title="200: OK SUCCESS" %}

```javascript
{
    "Data": {
        "isVerified": true
    },
    "Message": "",
    "Status": "SUCCESS"
}
```

{% endtab %}

{% tab title="401: Unauthorized Failure in authentication" %}

```javascript
{
    "message": "Invalid API key in request"
}
```

{% endtab %}

{% tab title="500: Internal Server Error Key values should be given" %}

```
{
    "message": "Internal Server Error"
}
```

{% endtab %}
{% endtabs %}

Take a look at how you might call this method using our official libraries, or via `curl`

{% tabs %}
{% tab title="curl" %}

```bash

curl --location 'https://api.krypcore.com/api/v0/devWallet/verifySignatureOffChain' \
--header 'DappId: **********' \
--header 'Authorization: **********' \
--header 'SubscriptionId: ********' \
--header 'ChainId: ********' \
--header 'Content-Type: application/json' \
--data '{
    "privateKey": "**********",
    "message": "Hello",
    "signature": "**********"
}'
```

{% endtab %}

{% tab title="Node.js (Fetch)" %}

```javascript

var myHeaders = new Headers();
myHeaders.append("DappId", "**********");
myHeaders.append("Authorization", "**********");
myHeaders.append("SubscriptionId", "********");
myHeaders.append("ChainId", "********");
myHeaders.append("Content-Type", "application/json");

var raw = JSON.stringify({
  "privateKey": "**********",
  "message": "Hello",
  "signature": "**********"
});

var requestOptions = {
  method: 'POST',
  headers: myHeaders,
  body: raw,
  redirect: 'follow'
};

fetch("https://api.krypcore.com/api/v0/devWallet/verifySignatureOffChain", requestOptions)
  .then(response => response.text())
  .then(result => console.log(result))
  .catch(error => console.log('error', error));
```

{% endtab %}

{% tab title="Python " %}

```python

import requests
import json

url = "https://api.krypcore.com/api/v0/devWallet/verifySignatureOffChain"

payload = json.dumps({
  "privateKey": "**********",
  "message": "Hello",
  "signature": "**********"
})
headers = {
  'DappId': '**********',
  'Authorization': '**********',
  'SubscriptionId': '********',
  'ChainId': '********',
  'Content-Type': 'application/json'
}

response = requests.request("POST", url, headers=headers, data=payload)

print(response.text)

```

{% endtab %}

{% tab title="Golang" %}

```go

package main

import (
  "fmt"
  "strings"
  "net/http"
  "io/ioutil"
)

func main() {

  url := "https://api.krypcore.com/api/v0/devWallet/verifySignatureOffChain"
  method := "POST"

  payload := strings.NewReader(`{
    "privateKey": "**********",
    "message": "Hello",
    "signature": "**********"
}`)

  client := &http.Client {
  }
  req, err := http.NewRequest(method, url, payload)

  if err != nil {
    fmt.Println(err)
    return
  }
  req.Header.Add("DappId", "**********")
  req.Header.Add("Authorization", "**********")
  req.Header.Add("SubscriptionId", "********")
  req.Header.Add("ChainId", "********")
  req.Header.Add("Content-Type", "application/json")

  res, err := client.Do(req)
  if err != nil {
    fmt.Println(err)
    return
  }
  defer res.Body.Close()

  body, err := ioutil.ReadAll(res.Body)
  if err != nil {
    fmt.Println(err)
    return
  }
  fmt.Println(string(body))
}
```

{% endtab %}
{% endtabs %}