diff --git a/src/Microsoft.AspNetCore.Authentication.Abstractions/AuthenticationProperties.cs b/src/Microsoft.AspNetCore.Authentication.Abstractions/AuthenticationProperties.cs
index 9d1e670ea8..271329209a 100644
--- a/src/Microsoft.AspNetCore.Authentication.Abstractions/AuthenticationProperties.cs
+++ b/src/Microsoft.AspNetCore.Authentication.Abstractions/AuthenticationProperties.cs
@@ -20,20 +20,29 @@ namespace Microsoft.AspNetCore.Authentication
         internal const string UtcDateTimeFormat = "r";
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="AuthenticationProperties"/> class
+        /// Initializes a new instance of the <see cref="AuthenticationProperties"/> class.
         /// </summary>
         public AuthenticationProperties()
-            : this(items: null)
-        {
-        }
+            : this(items: null, parameters: null)
+        { }
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="AuthenticationProperties"/> class
+        /// Initializes a new instance of the <see cref="AuthenticationProperties"/> class.
         /// </summary>
-        /// <param name="items"></param>
+        /// <param name="items">State values dictionary to use.</param>
         public AuthenticationProperties(IDictionary<string, string> items)
+            : this(items, parameters: null)
+        { }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AuthenticationProperties"/> class.
+        /// </summary>
+        /// <param name="items">State values dictionary to use.</param>
+        /// <param name="parameters">Parameters dictionary to use.</param>
+        public AuthenticationProperties(IDictionary<string, string> items, IDictionary<string, object> parameters)
         {
             Items = items ?? new Dictionary<string, string>(StringComparer.Ordinal);
+            Parameters = parameters ?? new Dictionary<string, object>(StringComparer.Ordinal);
         }
 
         /// <summary>
@@ -41,6 +50,12 @@ namespace Microsoft.AspNetCore.Authentication
         /// </summary>
         public IDictionary<string, string> Items { get; }
 
+        /// <summary>
+        /// Collection of parameters that are passed to the authentication handler. These are not intended for
+        /// serialization or persistence, only for flowing data between call sites.
+        /// </summary>
+        public IDictionary<string, object> Parameters { get; }
+
         /// <summary>
         /// Gets or sets whether the authentication session is persisted across multiple requests.
         /// </summary>
@@ -86,12 +101,22 @@ namespace Microsoft.AspNetCore.Authentication
             set => SetBool(RefreshKey, value);
         }
 
-        private string GetString(string key)
+        /// <summary>
+        /// Get a string value from the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <returns>Retrieved value or <c>null</c> if the property is not set.</returns>
+        public string GetString(string key)
         {
             return Items.TryGetValue(key, out string value) ? value : null;
         }
 
-        private void SetString(string key, string value)
+        /// <summary>
+        /// Set a string value in the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <param name="value">Value to set or <c>null</c> to remove the property.</param>
+        public void SetString(string key, string value)
         {
             if (value != null)
             {
@@ -103,16 +128,44 @@ namespace Microsoft.AspNetCore.Authentication
             }
         }
 
-        private bool? GetBool(string key)
+        /// <summary>
+        /// Get a parameter from the <see cref="Parameters"/> collection.
+        /// </summary>
+        /// <typeparam name="T">Parameter type.</typeparam>
+        /// <param name="key">Parameter key.</param>
+        /// <returns>Retrieved value or the default value if the property is not set.</returns>
+        public T GetParameter<T>(string key)
+            => Parameters.TryGetValue(key, out var obj) && obj is T value ? value : default;
+
+        /// <summary>
+        /// Set a parameter value in the <see cref="Parameters"/> collection.
+        /// </summary>
+        /// <typeparam name="T">Parameter type.</typeparam>
+        /// <param name="key">Parameter key.</param>
+        /// <param name="value">Value to set.</param>
+        public void SetParameter<T>(string key, T value)
+            => Parameters[key] = value;
+
+        /// <summary>
+        /// Get a bool value from the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <returns>Retrieved value or <c>null</c> if the property is not set.</returns>
+        protected bool? GetBool(string key)
         {
-            if (Items.TryGetValue(key, out string value) && bool.TryParse(value, out bool refresh))
+            if (Items.TryGetValue(key, out string value) && bool.TryParse(value, out bool boolValue))
             {
-                return refresh;
+                return boolValue;
             }
             return null;
         }
 
-        private void SetBool(string key, bool? value)
+        /// <summary>
+        /// Set a bool value in the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <param name="value">Value to set or <c>null</c> to remove the property.</param>
+        protected void SetBool(string key, bool? value)
         {
             if (value.HasValue)
             {
@@ -124,7 +177,12 @@ namespace Microsoft.AspNetCore.Authentication
             }
         }
 
-        private DateTimeOffset? GetDateTimeOffset(string key)
+        /// <summary>
+        /// Get a DateTimeOffset value from the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <returns>Retrieved value or <c>null</c> if the property is not set.</returns>
+        protected DateTimeOffset? GetDateTimeOffset(string key)
         {
             if (Items.TryGetValue(key, out string value)
                 && DateTimeOffset.TryParseExact(value, UtcDateTimeFormat, CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind, out DateTimeOffset dateTimeOffset))
@@ -134,7 +192,12 @@ namespace Microsoft.AspNetCore.Authentication
             return null;
         }
 
-        private void SetDateTimeOffset(string key, DateTimeOffset? value)
+        /// <summary>
+        /// Set a DateTimeOffset value in the <see cref="Items"/> collection.
+        /// </summary>
+        /// <param name="key">Property key.</param>
+        /// <param name="value">Value to set or <c>null</c> to remove the property.</param>
+        protected void SetDateTimeOffset(string key, DateTimeOffset? value)
         {
             if (value.HasValue)
             {
diff --git a/test/Microsoft.AspNetCore.Authentication.Core.Test/AuthenticationPropertiesTests.cs b/test/Microsoft.AspNetCore.Authentication.Core.Test/AuthenticationPropertiesTests.cs
new file mode 100644
index 0000000000..639c9b558e
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Authentication.Core.Test/AuthenticationPropertiesTests.cs
@@ -0,0 +1,207 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Authentication.Core.Test
+{
+    public class AuthenticationPropertiesTests
+    {
+        [Fact]
+        public void DefaultConstructor_EmptyCollections()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Empty(props.Items);
+            Assert.Empty(props.Parameters);
+        }
+
+        [Fact]
+        public void ItemsConstructor_ReusesItemsDictionary()
+        {
+            var items = new Dictionary<string, string>
+            {
+                ["foo"] = "bar",
+            };
+            var props = new AuthenticationProperties(items);
+            Assert.Same(items, props.Items);
+            Assert.Empty(props.Parameters);
+        }
+
+        [Fact]
+        public void FullConstructor_ReusesDictionaries()
+        {
+            var items = new Dictionary<string, string>
+            {
+                ["foo"] = "bar",
+            };
+            var parameters = new Dictionary<string, object>
+            {
+                ["number"] = 1234,
+                ["list"] = new List<string> { "a", "b", "c" },
+            };
+            var props = new AuthenticationProperties(items, parameters);
+            Assert.Same(items, props.Items);
+            Assert.Same(parameters, props.Parameters);
+        }
+
+        [Fact]
+        public void GetSetString()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.GetString("foo"));
+            Assert.Equal(0, props.Items.Count);
+
+            props.SetString("foo", "foo bar");
+            Assert.Equal("foo bar", props.GetString("foo"));
+            Assert.Equal("foo bar", props.Items["foo"]);
+            Assert.Equal(1, props.Items.Count);
+
+            props.SetString("foo", "foo baz");
+            Assert.Equal("foo baz", props.GetString("foo"));
+            Assert.Equal("foo baz", props.Items["foo"]);
+            Assert.Equal(1, props.Items.Count);
+
+            props.SetString("bar", "xy");
+            Assert.Equal("xy", props.GetString("bar"));
+            Assert.Equal("xy", props.Items["bar"]);
+            Assert.Equal(2, props.Items.Count);
+
+            props.SetString("bar", string.Empty);
+            Assert.Equal(string.Empty, props.GetString("bar"));
+            Assert.Equal(string.Empty, props.Items["bar"]);
+
+            props.SetString("foo", null);
+            Assert.Null(props.GetString("foo"));
+            Assert.Equal(1, props.Items.Count);
+        }
+
+        [Fact]
+        public void GetSetParameter_String()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.GetParameter<string>("foo"));
+            Assert.Equal(0, props.Parameters.Count);
+
+            props.SetParameter<string>("foo", "foo bar");
+            Assert.Equal("foo bar", props.GetParameter<string>("foo"));
+            Assert.Equal("foo bar", props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+
+            props.SetParameter<string>("foo", null);
+            Assert.Null(props.GetParameter<string>("foo"));
+            Assert.Null(props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+        }
+
+        [Fact]
+        public void GetSetParameter_Int()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.GetParameter<int?>("foo"));
+            Assert.Equal(0, props.Parameters.Count);
+
+            props.SetParameter<int?>("foo", 123);
+            Assert.Equal(123, props.GetParameter<int?>("foo"));
+            Assert.Equal(123, props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+
+            props.SetParameter<int?>("foo", null);
+            Assert.Null(props.GetParameter<int?>("foo"));
+            Assert.Null(props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+        }
+
+        [Fact]
+        public void GetSetParameter_Collection()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.GetParameter<int?>("foo"));
+            Assert.Equal(0, props.Parameters.Count);
+
+            var list = new string[] { "a", "b", "c" };
+            props.SetParameter<ICollection<string>>("foo", list);
+            Assert.Equal(new string[] { "a", "b", "c" }, props.GetParameter<ICollection<string>>("foo"));
+            Assert.Same(list, props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+
+            props.SetParameter<ICollection<string>>("foo", null);
+            Assert.Null(props.GetParameter<ICollection<string>>("foo"));
+            Assert.Null(props.Parameters["foo"]);
+            Assert.Equal(1, props.Parameters.Count);
+        }
+
+        [Fact]
+        public void IsPersistent_Test()
+        {
+            var props = new AuthenticationProperties();
+            Assert.False(props.IsPersistent);
+
+            props.IsPersistent = true;
+            Assert.True(props.IsPersistent);
+            Assert.Equal(string.Empty, props.Items.First().Value);
+
+            props.Items.Clear();
+            Assert.False(props.IsPersistent);
+        }
+
+        [Fact]
+        public void RedirectUri_Test()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.RedirectUri);
+
+            props.RedirectUri = "http://example.com";
+            Assert.Equal("http://example.com", props.RedirectUri);
+            Assert.Equal("http://example.com", props.Items.First().Value);
+
+            props.Items.Clear();
+            Assert.Null(props.RedirectUri);
+        }
+
+        [Fact]
+        public void IssuedUtc_Test()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.IssuedUtc);
+
+            props.IssuedUtc = new DateTimeOffset(new DateTime(2018, 03, 21, 0, 0, 0, DateTimeKind.Utc));
+            Assert.Equal(new DateTimeOffset(new DateTime(2018, 03, 21, 0, 0, 0, DateTimeKind.Utc)), props.IssuedUtc);
+            Assert.Equal("Wed, 21 Mar 2018 00:00:00 GMT", props.Items.First().Value);
+
+            props.Items.Clear();
+            Assert.Null(props.IssuedUtc);
+        }
+
+        [Fact]
+        public void ExpiresUtc_Test()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.ExpiresUtc);
+
+            props.ExpiresUtc = new DateTimeOffset(new DateTime(2018, 03, 19, 12, 34, 56, DateTimeKind.Utc));
+            Assert.Equal(new DateTimeOffset(new DateTime(2018, 03, 19, 12, 34, 56, DateTimeKind.Utc)), props.ExpiresUtc);
+            Assert.Equal("Mon, 19 Mar 2018 12:34:56 GMT", props.Items.First().Value);
+
+            props.Items.Clear();
+            Assert.Null(props.ExpiresUtc);
+        }
+
+        [Fact]
+        public void AllowRefresh_Test()
+        {
+            var props = new AuthenticationProperties();
+            Assert.Null(props.AllowRefresh);
+
+            props.AllowRefresh = true;
+            Assert.True(props.AllowRefresh);
+            Assert.Equal("True", props.Items.First().Value);
+
+            props.AllowRefresh = false;
+            Assert.False(props.AllowRefresh);
+            Assert.Equal("False", props.Items.First().Value);
+
+            props.Items.Clear();
+            Assert.Null(props.AllowRefresh);
+        }
+    }
+}