All requests made by Plivo to your server URLs contain X-Plivo-Signature-V2, X-Plivo-Signature-Ma-V2, and X-Plivo-Signature-V2-Nonce HTTP headers. To validate a request and to verify that the request to your server originated from Plivo, you must generate a signature at your end and check that it matches with the X-Plivo-Signature-V2 or X-Plivo-Signature-Ma-V2 parameter in the HTTP header.

You can use either X-Plivo-Signature-V2 or X-Plivo-Signature-Ma-V2 to validate a signature.

  • X-Plivo-Signature-V2 is generated using the Auth Token of the associated account or subaccount. To validate using the X-Plivo-Signature-V2 request header, you must generate a signature at your end using the same account or subaccount.
  • X-Plivo-Signature-Ma-V2 is always generated using the Auth Token of the main account. To validate using the X-Plivo-Signature-Ma-V2 request header, you must generate the signature using the main account.

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Generating and validating the signature

You can generate the signature by calculating the keyed hash message authentication code (HMAC) with these parameters:

  • Key — Your Plivo Auth Token
  • Message — Base URI appended with X-Plivo-Signature-V2-Nonce. For example, if the base URI is https://<yourdomain>.com/answer/ and X-Plivo-Signature-V2-Nonce is 05429567804466091622, the message will be https://<yourdomain>.com/answer/05429567804466091622.
  • Hashing Function — SHA256

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Validating signatures using the latest server SDKs

To validate and verify that the request to your server has originated from Plivo, you must compare the generated signature with X-Plivo-Signature-V2 parameter in the HTTP header and check whether they’re identical. You’ll need your Auth Token, X-Plivo-Signature-V2-Nonce, and the original URL of the server to which callback was sent.

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Code

from flask import Flask, request, make_response, url_for
import plivo

app = Flask(__name__)

@app.route('/receive_sms/', methods =['GET','POST'])
def signature():
    signature = request.headers.get('X-Plivo-Signature-V2')
    nonce = request.headers.get('X-Plivo-Signature-V2-Nonce')
    uri = url_for('signature', _external=True)
    auth_token = "<auth_token>"
    
    output = plivo.utils.validate_signature(uri,nonce,signature,auth_token)
    print(output)

    from_number = request.values.get('From') # Sender's phone numer
    to_number = request.values.get('To') # Receiver's phone number - Plivo number
    text = request.values.get('Text') # The text which was received

    print('Message received - From: %s, To: %s, Text: %s' %(from_number, to_number, text))
    return "Text received"

if __name__ == "__main__":
    app.run(host='0.0.0.0', debug=True)