如何加密通过请求发送到我的服务器的params？

Question

我将HTTPS请求发送到Node JS服务器。我在Swift中使用URLSession，我想加密我发送的数据，这样就无法读取它们。

以下是我的代码：

let boundary=generate_boundary_string()
var request=URLRequest(url: url)
request.httpMethod="POST"
request.setValue("multipart/form-data; boundary"+boundary, forHTTPHeaderField: "Content-Type")
request.setValue(token, forHTTPHeaderField: "authorization")

//prepare body with params
let body=NSMutableData()
for (key, value) in params{
    body.appendString("--\(boundary)\r\n")
    body.appendString("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n")
    body.appendString("\(value)\r\n")
}
request.httpBody=body

//send the request
let session=URLSession.shared
let task=session.dataTask(with: request, completionHandler: {data, response, error in
    guard data != nil else{return}

    //decode received data
    //...
}).resume()

我该怎么办？