Adobe Sign API password protection not working

Question

I am uploading an agreement to Adobe Sign that needs password protection. Per https://secure.na1.adobesign.com/public/docs/restapi/v6 I should include

"securityOption":{
  "openPassword":"0123456789"
}

The separate article https://helpx.adobe.com/sign/kb/how-to-set-open-password-for-a-signed-document-using-rest-api-adobe-sign.html says the key should be securityOptions, but even when including both in the payload it still doesn't seem to take. Here is the full payload with excessive options filled in:

{
   "signatureType":"ESIGN",
   "state":"IN_PROCESS",
   "participantSetsInfo":[
      {
         "order":1,
         "role":"SIGNER",
         "memberInfos":[
            {
               "email":"[email protected]",
               "securityOption":{
                  "openPassword":"XXXXXXXXXX",
                  "protectOpen":true
               },
               "securityOptions":{
                  "openPassword":"XXXXXXXXXX",
                  "protectOpen":true
               }
            }
         ]
      }
   ],
   "signatureFlow":"SENDER_SIGNATURE_NOT_REQUIRED",
   "fileInfos":[
      {
         "transientDocumentId":"XXXXXXXXXX"
      }
   ],
   "name":"Passworded Agreement",
   "securityOption":{
      "openPassword":"XXXXXXXXXX",
      "protectOpen":true
   },
   "securityOptions":{
      "openPassword":"XXXXXXXXXX",
      "protectOpen":true
   }
}

Where am I going wrong with the field(s)?

Answer 1

There are a few different places for security to be applied to the document. The securityOption field at the top only protects management of the document and does not enforce a password for signers. That should be done through participantSetsInfo and the securityOption and must include authenticationMethod as 'PASSWORD'. You can drop the securityOptions fields as well as the article is incorrect and those names are not part of the specification.