{
  "data": {
    "incident": {
      "end_time": null,
      "id": "INCIDENT_MEDIUM_KarurVysyaBank_a7259c79-25a8-4b86-bcab-71562a85c386",
      "impact": "MEDIUM",
      "message": "We are facing issues with KVB bank UPI payments. ",
      "start_time": "2021-04-16T14:00:00+05:30",
      "status": "OPEN",
      "type": "UNSCHEDULED"
    },
    "instruments": {
      "upi": {
        "issuers": [
          "Karur Vysya Bank"
        ]
      }
    }
  },
  "event_time": "2021-04-16T14:10:36+05:30",
  "type": "HEALTH_ALERT",
  "version": 1
}

{
  "data": {
    "incident": {
      "end_time": "2021-04-16T18:20:24+05:30",
      "id": "INCIDENT_MEDIUM_KarurVysyaBank_a7259c79-25a8-4b86-bcab-71562a85c386",
      "impact": "MEDIUM",
      "message": "Payment mode up",
      "start_time": "2021-04-16T14:00:00+05:30",
      "status": "RESOLVED",
      "type": "UNSCHEDULED"
    },
    "instruments": {
      "upi": {
        "issuers": [
          "Karur Vysya Bank"
        ]
      }
    }
  },
  "event_time": "2021-04-16T18:20:24+05:30",
  "type": "HEALTH_ALERT",
  "version": 1
}

//The payload here refers to the raw request sent by 
Cashfree to your endpoint. No modifications need to be 
done to this payload.

payload := {"data":{"bank_name":"Test Bank",
"card_type":"Visa","health":"DEGRADED",
"incident_end_time":"2021-04-07T00:20:30",
"incident_id":"INCIDENT_HIGH_Test Bank_954b95zz-f11a-test-abcd-0eb0e8608847",
"incident_impact":"High",
"incident_start_time":"2021-04-06T00:20",
"incident_type":"Scheduled",
"is_resolved":false,
"issuers":[],
"message":"We are facing high failure issues in Payment gateway at the moment and will keep you updated about the issue.",
"payment_gateway":null,"payment_mode":"DEBIT_CARD",
"scope":"PaymentMode"},
"type":"HEALTH_ALERT","version":1}

# timestamp is present in the header x-cashfree-timestamp
timestamp := 1617695238078

signedPayload := $timestamp.$payload

expectedSignature := Base64Encode(HMACSHA256($signedPayload, $merchantSecretKey))

function verify(ts, rawBody){
    const body = ts + rawBody
    const secretKey = "<your secret key>";
    let genSignature = crypto.createHmac('sha256',secretKey).update(body).digest("base64");
    return genSignature
}

func VerifySignature(expectedSig string, ts int64, body string) (string, error) {
	t := time.Now()
	currentTS := t.Unix()
	if currentTS-ts > 1000*300 {
		return "", errors.New("webhook delivered too late")
	}
	signStr := strconv.FormatInt(ts, 10) + body
	fmt.Println("signing String: ", signStr)
	key := ""
	h := hmac.New(sha256.New, []byte(key))
	h.Write([]byte(signStr))
	b := h.Sum(nil)
	return base64.StdEncoding.EncodeToString(b), nil
}

function computeSignature($ts, $rawBody){
    $signStr = $ts . $rawBody;
    $key = "";
    $computeSig = base64_encode(hash_hmac('sha256', $signStr, $key, true));
    return $computeSig;
}

public String generateSignature() {
 	String payload = "json payload in string";
  String timestamp = "x-webhook-timestamp";
  String data = timestamp+payload;

  String secretKey = "SECRET-KEY"; // Get secret key from Cashfree Merchant Dashboard;
  Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
  SecretKeySpec secret_key_spec = new SecretKeySpec(secretKey.getBytes(),"HmacSHA256");
  sha256_HMAC.init(secret_key_spec);
  String computed_signature = Base64.getEncoder().encodeToString(sha256_HMAC.doFinal(data.getBytes()));
  return computed_signature; // compare with "x-webhook-signature"
}

import base64
import hashlib
import hmac

def generateSignature():    
    timestamp = "timestamp data"
    payload = 'json data in string'
    signatureData = timestamp+payload
    message = bytes(signatureData, 'utf-8')
    secretkey=bytes("Secret_Key",'utf-8') #Get Secret_Key from Cashfree Merchant Dashboard.
    signature = base64.b64encode(hmac.new(secretkey, message, digestmod=hashlib.sha256).digest())
    computed_signature = str(signature, encoding='utf8')
    return computed_signature #compare with "x-webhook-signature"