Dropbox Sign でマスクされたデータを取得して表示する方法

{
"event": {
"event_type":"signature_request_signed",
"event_time":"1609432599",
"event_hash":"5118da82b71d394887382d21e2488ae7a029d7ab",
"event_metadata": {
"related_signature_id":"d91adbb59792d036264057",
"reported_for_account_id":"f0899a9b5354b22b6cc6b301",
"reported_for_app_id":"d8754524aaa29c3025bd3"
      }
  },
"account_guid":"f0899a9b5354b24263252b6cc6b301",
"client_id":"d8754524aaa6129c3025bd3",
"signature_request": {
"signature_request_id":"aaf05626ad486775234c3e4043",
"test_mode": true,
"title":"test masked SSN",
"original_title":"masked SSN",
"subject":"masked SSN",
"message": null,
"metadata": {
"signed_on_domain":"localhost"
  },
"created_at": 1609432502,
"is_complete": false,
"is_declined": false,
"has_error": false,
"custom_fields":[],
"response_data":[{
"name":"Signature1",
"type":"signature",
"required": true,
"api_id":"97f86e0633f7",
"value": null,
"signature_id":"d91adbb597920fcd036264057"
          },
          {
"name":"Masked SSN Field",
"type":"text",
"required": true,
"api_id":"acf4bb6fd352",
"value":"*********",
"signature_id":"d91adbb59792fcd036264057"
          }
      ],
"signing_url": null,
"signing_redirect_url": null,
"final_copy_uri":"/v3/signature_request/final_copy/aaf05626a1fafa35234c3e4043",
"files_url":"https://api.hellosign.com/v3/signature_request/files/aaf05626ad486775234c3e4043",
"details_url":"https://app.hellosign.com/home/manage?guid=aaf05626ad486775234c3e4043",
"requester_email_address":"jack@example.com",
"signatures":[{
"signature_id":"d91adbb5979d036264057",
"has_pin": false,
"has_sms_auth": false,
"signer_email_address":"jill@example.com",
"signer_name":"Jill",
"signer_role": 1,
"order": null,
"status_code":"signed",
"signed_at": 1609432599,
"last_viewed_at": 1609432578,
"last_reminded_at": null,
"error": null
   }],
"cc_email_addresses":[],
"template_ids": [
"7b3d2693ad423a39a2dd104"
      ],
"client_id":"d8754524aaa6129c3025bd3"
  }
} 

{
"signature_request": {
"signature_request_id": "aaf05626ad486775234c3e4043",
"test_mode": true,
"title": "test masked SSN",
"original_title": "masked SSN",
"subject": "masked SSN",
"message": null,
"metadata": {
"signed_on_domain": "localhost"
},
"created_at": 1609432502,
"is_complete": true,
"is_declined": false,
"has_error": false,
"custom_fields": [ ],
"response_data": [{
"name": "Signature1",
"type": "signature",
"required": true,
"api_id": "97f86e0633f7",
"value": null,
"signature_id": "d91adbb597920fcd036264057"
},
{
"name": "Masked SSN Field",
"type": "text",
"required": true,
"api_id": "e2b418c6-2498-44af-b73f-acf4bb6fd352",
"value": "123-45-6789",
"signature_id": "d91adbb59792fcd036264057"
"masked": true
}
],
"signing_url": null,
"signing_redirect_url": null,
"final_copy_uri": "/v3/signature_request/final_copy/aaf05626a1fafa35234c3e4043",
"files_url": "https://api.hellosign.com/v3/signature_request/files/aaf05626a1fafa35234c3e4043",
"details_url": "https://app.hellosign.com/home/manage?guid=aaf05626a1fafa35234c3e4043",
"requester_email_address": "hazem.hamed@hellosign.com",
"signatures": [{
"signature_id": "d91adbb5979d036264057",
"has_pin": false,
"has_sms_auth": false,
"signer_email_address": "jhondoe1@test.com",
"signer_name": "John Doe",
"signer_role": 1,
"order": null,
"status_code": "signed",
"signed_at": 1609432599,
"last_viewed_at": 1609432578,
"last_reminded_at": null,
"error": null
}],
"cc_email_addresses": [],
"template_ids": [
"7b3d2693ad423a39a2dd104"
],
"client_id": "d8754524aaa6129c3025bd3"
}
}