using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

        {

          ""users"": [

            {

              ""id"": 5,

              ""name"": ""Peter Gibbons"",

              ""company"": ""Initech"",

              ""login"": ""pgibbons"",

              ""password"": ""Sup3rS3cr3tP@ssw0rd!"",

              ""financialDetails"": {

                ""creditCards"": [

                  {

                    ""vendor"": ""Viza"",

                    ""cardNumber"": ""1000200030004000"",

                    ""expDate"": ""2017-10-18"",

                    ""securityCode"": 123,

                    ""lastUse"": ""2016-10-15""

                  },

                  {

                    ""vendor"": ""MasterCharge"",

                    ""cardNumber"": ""1001200230034004"",

                    ""expDate"": ""2018-05-21"",

                    ""securityCode"": 789,

                    ""lastUse"": ""2016-10-02""

                  }

                ],

                ""bankAccounts"": [

                  {

                    ""accountType"": ""checking"",

                    ""accountNumber"": ""12345678901"",

                    ""financialInsitution"": ""1st Bank of USA"",

                    ""routingNumber"": ""012345670""

                  }

                ]

              },

              ""securityAnswers"":

              [

                  ""Constantinople"",

                  ""Goldfinkle"",

                  ""Poppykosh"",

              ],

              ""interests"": ""Computer security, numbers and passwords""

            }

          ]

        }";

        Regex[] regexes = new Regex[]

        {

            new Regex("^.*password.*$", RegexOptions.IgnoreCase),

            new Regex("^.*number$", RegexOptions.IgnoreCase),

            new Regex("^expDate$", RegexOptions.IgnoreCase),

            new Regex("^security.*$", RegexOptions.IgnoreCase),

        };

        string redactedJson = RemoveSensitiveProperties(json, regexes);

        Console.WriteLine(redactedJson);    

    }

    public static string RemoveSensitiveProperties(string json, IEnumerable<Regex> regexes)

    {

        JToken token = JToken.Parse(json);

        RemoveSensitiveProperties(token, regexes);

        return token.ToString();

    }

    public static void RemoveSensitiveProperties(JToken token, IEnumerable<Regex> regexes)

    {

        if (token.Type == JTokenType.Object)

        {

            foreach (JProperty prop in token.Children<JProperty>().ToList())

            {

                bool removed = false;

                foreach (Regex regex in regexes)

                {

                    if (regex.IsMatch(prop.Name))

                    {

                        prop.Remove();

                        removed = true;

                        break;

                    }

                }

                if (!removed)

                {

                    RemoveSensitiveProperties(prop.Value, regexes);

                }

            }

        }

        else if (token.Type == JTokenType.Array)

        {

            foreach (JToken child in token.Children())

            {

                RemoveSensitiveProperties(child, regexes);

            }

        }

    }   

}