diff --git a/OpenSim/Data/MySQL/MySQLXAssetData.cs b/OpenSim/Data/MySQL/MySQLXAssetData.cs
index 0aff61824b..4cb89fa9e3 100644
--- a/OpenSim/Data/MySQL/MySQLXAssetData.cs
+++ b/OpenSim/Data/MySQL/MySQLXAssetData.cs
@@ -31,6 +31,7 @@ using System.Data;
 using System.IO;
 using System.IO.Compression;
 using System.Reflection;
+using System.Security.Cryptography;
 using System.Text;
 using log4net;
 using MySql.Data.MySqlClient;
@@ -44,15 +45,20 @@ namespace OpenSim.Data.MySQL
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
-        private bool m_enableCompression = false;
-        private string m_connectionString;
-        private object m_dbLock = new object();
-
         protected virtual Assembly Assembly
         {
             get { return GetType().Assembly; }
         }
 
+        private bool m_enableCompression = false;
+        private string m_connectionString;
+        private object m_dbLock = new object();
+
+        /// <summary>
+        /// We can reuse this for all hashing since all methods are single-threaded through m_dbBLock
+        /// </summary>
+        private HashAlgorithm hasher = new SHA256CryptoServiceProvider();
+
         #region IPlugin Members
 
         public override string Version { get { return "1.0.0.0"; } }
@@ -213,7 +219,7 @@ namespace OpenSim.Data.MySQL
                             }
                         }
 
-                        string hash = Util.SHA1Hash(asset.Data);
+                        byte[] hash = hasher.ComputeHash(asset.Data);
 
 //                        m_log.DebugFormat(
 //                            "[XASSET DB]: Compressed data size for {0} {1}, hash {2} is {3}",
@@ -328,7 +334,7 @@ namespace OpenSim.Data.MySQL
         /// <param name="transaction"></param>
         /// <param name="hash"></param>
         /// <returns></returns>
-        private bool ExistsData(MySqlConnection dbcon, MySqlTransaction transaction, string hash)
+        private bool ExistsData(MySqlConnection dbcon, MySqlTransaction transaction, byte[] hash)
         {
 //            m_log.DebugFormat("[ASSETS DB]: Checking for asset {0}", uuid);
 
@@ -438,7 +444,9 @@ namespace OpenSim.Data.MySQL
                                 metadata.Flags = (AssetFlags)Convert.ToInt32(dbReader["asset_flags"]);
                                 metadata.FullID = DBGuid.FromDB(dbReader["id"]);
                                 metadata.CreatorID = dbReader["creator_id"].ToString();
-                                metadata.SHA1 = Encoding.Default.GetBytes((string)dbReader["hash"]);
+
+                                // We'll ignore this for now - it appears unused!
+//                                metadata.SHA1 = dbReader["hash"]);
 
                                 retList.Add(metadata);
                             }
diff --git a/OpenSim/Data/MySQL/Resources/XAssetStore.migrations b/OpenSim/Data/MySQL/Resources/XAssetStore.migrations
index b89eab27f5..d3cca5e884 100644
--- a/OpenSim/Data/MySQL/Resources/XAssetStore.migrations
+++ b/OpenSim/Data/MySQL/Resources/XAssetStore.migrations
@@ -5,7 +5,7 @@ BEGIN;
 
 CREATE TABLE `xassetsmeta` (
   `id` char(36) NOT NULL,
-  `hash` char(64) NOT NULL,
+  `hash` binary(32) NOT NULL,
   `name` varchar(64) NOT NULL,
   `description` varchar(64) NOT NULL,
   `asset_type` tinyint(4) NOT NULL,
@@ -19,7 +19,7 @@ CREATE TABLE `xassetsmeta` (
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Version 1';
 
 CREATE TABLE `xassetsdata` (
-  `hash` char(64) NOT NULL,
+  `hash` binary(32) NOT NULL,
   `data` longblob NOT NULL,
   PRIMARY KEY (`hash`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Version 1';
diff --git a/prebuild.xml b/prebuild.xml
index 79814ac2b2..030d232898 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -2051,9 +2051,10 @@
 
       <ReferencePath>../../../bin/</ReferencePath>
       <Reference name="System"/>
-      <Reference name="System.Xml"/>
+      <Reference name="System.Core"/>
       <Reference name="System.Data"/>
       <Reference name="System.Drawing"/>
+      <Reference name="System.Xml"/>
       <Reference name="OpenSim.Framework"/>
       <Reference name="OpenSim.Data"/>
       <Reference name="OpenMetaverseTypes" path="../../../bin/"/>