From 3bda7b656552f0f12a4c5823aa8c298d1ae4c91b Mon Sep 17 00:00:00 2001
From: Catcher Wong <catcher_hwq@outlook.com>
Date: Fri, 29 Sep 2017 08:51:23 +0800
Subject: [PATCH 1/4] create a enum to define length of MD5 hash.

---
 src/NETCore.Encrypt/Internal/MD5Length.cs | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 src/NETCore.Encrypt/Internal/MD5Length.cs

diff --git a/src/NETCore.Encrypt/Internal/MD5Length.cs b/src/NETCore.Encrypt/Internal/MD5Length.cs
new file mode 100644
index 0000000..4c6c31c
--- /dev/null
+++ b/src/NETCore.Encrypt/Internal/MD5Length.cs
@@ -0,0 +1,8 @@
+namespace NETCore.Encrypt
+{
+    public enum MD5Length
+    {
+        L16 = 16,
+        L32 = 32
+    }
+}

From 1eabf1c22de4b75b4923ff7035ed106a7674a53d Mon Sep 17 00:00:00 2001
From: Catcher Wong <catcher_hwq@outlook.com>
Date: Fri, 29 Sep 2017 08:54:44 +0800
Subject: [PATCH 2/4] MD5 hash result's length support 16 and 32.

---
 src/NETCore.Encrypt/EncryptProvider.cs | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/NETCore.Encrypt/EncryptProvider.cs b/src/NETCore.Encrypt/EncryptProvider.cs
index efb45f1..d192759 100644
--- a/src/NETCore.Encrypt/EncryptProvider.cs
+++ b/src/NETCore.Encrypt/EncryptProvider.cs
@@ -423,30 +423,35 @@ public static RSAKey CreateRsaKey(RsaSize rsaSize = RsaSize.R2048)
         #endregion
 
         #region MD5
-
         /// <summary>
         /// MD5 hash
         /// </summary>
-        /// <param name="srcString">The string to be encrypted</param>
+        /// <param name="srcString">The string to be encrypted.</param>
+        /// <param name="length">The length of hash result , default value is <see cref="MD5Length.L32"/>.</param>
         /// <returns></returns>
-        public static string Md5(string srcString)
+        public static string Md5(string srcString, MD5Length length = MD5Length.L32)
         {
             Check.Argument.IsNotEmpty(srcString, nameof(srcString));
 
+            string str_md5_out = string.Empty;
             using (MD5 md5 = MD5.Create())
             {
                 byte[] bytes_md5_in = Encoding.UTF8.GetBytes(srcString);
                 byte[] bytes_md5_out = md5.ComputeHash(bytes_md5_in);
-                string str_md5_out = BitConverter.ToString(bytes_md5_out);
+
+                str_md5_out = length == MD5Length.L32
+                    ? BitConverter.ToString(bytes_md5_out) 
+                    : BitConverter.ToString(bytes_md5_out, 4, 8);
+               
                 str_md5_out = str_md5_out.Replace("-", "");
                 return str_md5_out;
             }
-        }
+        }        
         #endregion
 
         #region HMACMD5
         /// <summary>
-        /// MD5 hash
+        /// HMACMD5 hash
         /// </summary>
         /// <param name="srcString">The string to be encrypted</param>
         /// <param name="key">encrypte key</param>

From 18c44c2a3693554afc840031e866c36c04f33f08 Mon Sep 17 00:00:00 2001
From: Catcher Wong <catcher_hwq@outlook.com>
Date: Fri, 29 Sep 2017 08:56:31 +0800
Subject: [PATCH 3/4] add MD5 test with length.

---
 test/NETCore.Encrypt.Tests/MD5_Tests.cs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/test/NETCore.Encrypt.Tests/MD5_Tests.cs b/test/NETCore.Encrypt.Tests/MD5_Tests.cs
index 5fc6ac3..d62f538 100644
--- a/test/NETCore.Encrypt.Tests/MD5_Tests.cs
+++ b/test/NETCore.Encrypt.Tests/MD5_Tests.cs
@@ -25,5 +25,16 @@ public void MD5_Error_Test()
         {
             Assert.Throws<ArgumentException>(() => EncryptProvider.Md5(string.Empty));
         }
+        
+        [Fact(DisplayName = "MD5 with length success test")]
+        public void MD5_With_Length_Success_Test()
+        {
+            var srcString = "Md5 test";
+
+            var hashed = EncryptProvider.Md5(srcString, MD5Length.L16);
+
+            Assert.NotEmpty(hashed);
+            Assert.Equal("69c6ecadb32f5492", hashed.ToLower());
+        }
     }
 }

From 419dc8b394be65d6e9b39812045b46353bff5a03 Mon Sep 17 00:00:00 2001
From: Catcher Wong <catcher_hwq@outlook.com>
Date: Fri, 29 Sep 2017 08:58:28 +0800
Subject: [PATCH 4/4] update the usage of MD5 hash with length

---
 README.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/README.md b/README.md
index 5eec056..aef3fd6 100644
--- a/README.md
+++ b/README.md
@@ -139,6 +139,13 @@ Install-Package NETCore.Encrypt -Version 2.0.2
   
   ```
   
+  ```csharp
+  
+  var srcString = "Md5 hash";
+  var hashed = EncryptProvider.Md5(srcString, MD5Length.L16);
+  
+  ```
+  
   ## SHA
   
   - #### SHA1