发布到 masspay API 时收到错误消息：
curl -X POST -H "Content-Type: application/json" -d '{"oauth_token":"", "pin":1234, "email":"", "filedata":"", "test":"true"}' https://masspay.dwollalabs.com/api/create/
收到：
TypeError: Not a string or buffer
at Object.module.exports.encrypt (/app/lib/utils.js:11:30)
at module.exports (/app/controllers/api.js:209:23)
at callbacks (/app/node_modules/express/lib/router/index.js:272:11)
at param (/app/node_modules/express/lib/router/index.js:246:11)
at pass (/app/node_modules/express/lib/router/index.js:253:5)
at Router._dispatch (/app/node_modules/express/lib/router/index.js:280:5)
at Object.middleware [as handle] (/app/node_modules/express/lib/router/index.js:45:10)
at next (/app/node_modules/express/node_modules/connect/lib/http.js:204:15)
at IncomingMessage.exports.parse.application/json (/app/node_modules/express/node_modules/connect/lib/middleware/bodyParser.js:137:7)
at IncomingMessage.EventEmitter.emit (events.js:93:17)
API 有问题还是我发送的内容有问题？