diff --git a/CryptoExchange.Net/Authentication/ApiCredentials.cs b/CryptoExchange.Net/Authentication/ApiCredentials.cs
index 141ff6a..f312ae3 100644
--- a/CryptoExchange.Net/Authentication/ApiCredentials.cs
+++ b/CryptoExchange.Net/Authentication/ApiCredentials.cs
@@ -1,27 +1,82 @@
 using System;
+using System.Security;
 
 namespace CryptoExchange.Net.Authentication
 {
-    public class ApiCredentials
+    public class ApiCredentials: IDisposable
     {
         /// <summary>
-        /// The api key
+        /// The api key to authenticate requests
         /// </summary>
-        public string Key { get; }
+        public SecureString Key { get; }
+
         /// <summary>
-        /// The api secret
+        /// The api secret to authenticate requests
         /// </summary>
-        public string Secret { get; }
+        public SecureString Secret { get; }
 
-        public ApiCredentials() { }
+        /// <summary>
+        /// The private key to authenticate requests
+        /// </summary>
+        public SecureString PrivateKey { get; }
 
-        public ApiCredentials(string key, string secret)
+        /// <summary>
+        /// Create Api credentials providing a private key for authenication
+        /// </summary>
+        /// <param name="privateKey">The private key used for signing</param>
+        public ApiCredentials(SecureString privateKey)
         {
-            if(string.IsNullOrEmpty(key) || string.IsNullOrEmpty(secret))
-                throw new ArgumentException("Apikey or apisecret not provided");
+            PrivateKey = Key;
+        }
 
+        /// <summary>
+        /// Create Api credentials providing a private key for authenication
+        /// </summary>
+        /// <param name="privateKey">The private key used for signing</param>
+        public ApiCredentials(string privateKey)
+        {
+            var securePrivateKey = new SecureString();
+            foreach (var c in privateKey)
+                securePrivateKey.AppendChar(c);
+            securePrivateKey.MakeReadOnly();
+            PrivateKey = securePrivateKey;
+        }
+
+        /// <summary>
+        /// Create Api credentials providing a api key and secret for authenciation
+        /// </summary>
+        /// <param name="key">The api key used for identification</param>
+        /// <param name="secret">The api secret used for signing</param>
+        public ApiCredentials(SecureString key, SecureString secret)
+        {
             Key = key;
             Secret = secret;
         }
+
+        /// <summary>
+        /// Create Api credentials providing a private key for authenication
+        /// </summary>
+        /// <param name="privateKey">The private key used for signing</param>
+        public ApiCredentials(string key, string secret)
+        {
+            var secureApiKey = new SecureString();
+            foreach (var c in key)
+                secureApiKey.AppendChar(c);
+            secureApiKey.MakeReadOnly();
+            Key = secureApiKey;
+
+            var secureApiSecret = new SecureString();
+            foreach (var c in secret)
+                secureApiSecret.AppendChar(c);
+            secureApiSecret.MakeReadOnly();
+            Secret = secureApiSecret;
+        }
+
+        public void Dispose()
+        {
+            Key?.Dispose();
+            Secret?.Dispose();
+            PrivateKey?.Dispose();
+        }
     }
 }
diff --git a/CryptoExchange.Net/Authentication/AuthenticationProvider.cs b/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
index 0dc3cd4..4dd1431 100644
--- a/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
+++ b/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
@@ -1,5 +1,4 @@
 using CryptoExchange.Net.Interfaces;
-using System.Security;
 
 namespace CryptoExchange.Net.Authentication
 {
@@ -7,18 +6,11 @@ namespace CryptoExchange.Net.Authentication
     {
         public ApiCredentials Credentials { get; }
 
-        public SecureString PrivateKey { get; }
-
         protected AuthenticationProvider(ApiCredentials credentials)
         {
             Credentials = credentials;
         }
 
-        protected AuthenticationProvider(SecureString privateKey)
-        {
-            PrivateKey = privateKey;
-        }
-
         public virtual string AddAuthenticationToUriString(string uri, bool signed)
         {
             return uri;    
diff --git a/CryptoExchange.Net/ExchangeClient.cs b/CryptoExchange.Net/ExchangeClient.cs
index 0606bff..6bf89cd 100644
--- a/CryptoExchange.Net/ExchangeClient.cs
+++ b/CryptoExchange.Net/ExchangeClient.cs
@@ -106,23 +106,12 @@ namespace CryptoExchange.Net
             string paramString = null;
             if (parameters != null)
             {
-                paramString = "with parameters ";
-                int paramCount = 1;
+                paramString = "with parameters";
+                
                 foreach (var param in parameters)
-                {
-                    string paramValue = param.Value.ToString();
-                    if (param.Value.GetType().IsArray)
-                        paramValue = string.Format("[{0}]", string.Join(", ", ((object[])param.Value).Select(p => p.ToString())));
+                    paramString += $" {param.Key}={(param.Value.GetType().IsArray ? $"[{string.Join(", ", ((object[])param.Value).Select(p => p.ToString()))}]": param.Value )},";
 
-                    paramString += $"{param.Key}={paramValue}";
-
-                    if (paramCount < parameters.Count)
-                        paramString += ", ";
-                    else
-                        paramString += ".";
-
-                    paramCount++;
-                }
+                paramString = paramString.Trim(',');
             }
 
             log.Write(LogVerbosity.Debug, $"Sending {(signed ? "signed" : "")} request to {request.Uri} {(paramString ?? "")}");
@@ -140,25 +129,13 @@ namespace CryptoExchange.Net
                     uriString += "?";
 
                 var arraysParameters = parameters.Where(p => p.Value.GetType().IsArray).ToList();
-                if (arraysParameters != null && arraysParameters.Count() > 0)
+                foreach(var arrayEntry in arraysParameters)
                 {
-                    bool isFirstEntry = true;
-                    arraysParameters.ForEach((arrayEntry) =>
-                    {
-                        if (!isFirstEntry)
-                            uriString += "&";
-
-                        List<object> values = ((object[])arrayEntry.Value).ToList();
-                        uriString += $"{string.Join("&", values.Select(v => $"{arrayEntry.Key}[]={v}"))}";
-
-                        isFirstEntry = false;
-                    });
-
-                    if (parameters.Count - arraysParameters.Count > 0)
-                        uriString += "&";
+                    uriString += $"{string.Join("&", ((object[])arrayEntry.Value).Select(v => $"{arrayEntry.Key}[]={v}"))}&";
                 }
 
                 uriString += $"{string.Join("&", parameters.Where(p => !p.Value.GetType().IsArray).Select(s => $"{s.Key}={s.Value}"))}";
+                uriString = uriString.TrimEnd('&');
             }
 
             if (authProvider != null)
@@ -272,6 +249,10 @@ namespace CryptoExchange.Net
 
         private void CheckObject(Type type, JObject obj)
         {
+            if (type.GetCustomAttribute<JsonConverterAttribute>(true) != null)
+                // If type has a custom JsonConverter we assume this will handle property mapping
+                return;
+
             bool isDif = false;
             var properties = new List<string>();
             var props = type.GetProperties();
@@ -291,12 +272,8 @@ namespace CryptoExchange.Net
                 {
                     d = properties.SingleOrDefault(p => p.ToLower() == token.Key.ToLower());
                     if (d == null && !(type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Dictionary<,>)))
-                    {
-                        // Checking if missing properties is voluntary
-                        // True : If entire class is handled by a JsonConveter
-                        bool isManuallyDeserialized = type.GetCustomAttribute<JsonConverterAttribute>(true) != null;
-                        if (!isManuallyDeserialized)
-                            log.Write(LogVerbosity.Warning, $"Didn't find property `{token.Key}` in object of type `{type.Name}`");
+                    {                        
+                        log.Write(LogVerbosity.Warning, $"Didn't find property `{token.Key}` in object of type `{type.Name}`");
                         isDif = true;
                         continue;
                     }
@@ -359,6 +336,7 @@ namespace CryptoExchange.Net
 
         public virtual void Dispose()
         {
+            authProvider?.Credentials?.Dispose();
             log.Write(LogVerbosity.Debug, "Disposing exchange client");
         }
     }
diff --git a/CryptoExchange.Net/ExchangeOptions.cs b/CryptoExchange.Net/ExchangeOptions.cs
index 0ce7720..b2629da 100644
--- a/CryptoExchange.Net/ExchangeOptions.cs
+++ b/CryptoExchange.Net/ExchangeOptions.cs
@@ -1,6 +1,5 @@
 using System.Collections.Generic;
 using System.IO;
-using System.Security;
 using CryptoExchange.Net.Authentication;
 using CryptoExchange.Net.Logging;
 using CryptoExchange.Net.RateLimiter;
@@ -18,11 +17,6 @@ namespace CryptoExchange.Net
         /// </summary>
         public ApiCredentials ApiCredentials { get; set; }
 
-        /// <summary>
-        /// The private key instead of api credentials
-        /// </summary>
-        public SecureString PrivateKey { get; set; }
-
         /// <summary>
         /// Proxy to use
         /// </summary>
diff --git a/CryptoExchange.Net/ExtensionMethods.cs b/CryptoExchange.Net/ExtensionMethods.cs
index 83dec83..f3fc934 100644
--- a/CryptoExchange.Net/ExtensionMethods.cs
+++ b/CryptoExchange.Net/ExtensionMethods.cs
@@ -1,4 +1,7 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Security;
 
 namespace CryptoExchange.Net
 {
@@ -25,5 +28,30 @@ namespace CryptoExchange.Net
             if (value != null)
                 parameters.Add(key, value);
         }
+
+        public static string GetString(this SecureString source)
+        {
+            string result = null;
+            int length = source.Length;
+            IntPtr pointer = IntPtr.Zero;
+            char[] chars = new char[length];
+
+            try
+            {
+                pointer = Marshal.SecureStringToBSTR(source);
+                Marshal.Copy(pointer, chars, 0, length);
+
+                result = string.Join("", chars);
+            }
+            finally
+            {
+                if (pointer != IntPtr.Zero)
+                {
+                    Marshal.ZeroFreeBSTR(pointer);
+                }
+            }
+
+            return result;
+        }
     }
 }