diff --git a/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/Excel/XLWorkbook_Load.cs
index 6df9e8e..b558cb2 100644
--- a/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -2174,7 +2174,18 @@
             if (sp == null) return;
 
             if (sp.Sheet != null) ws.Protection.Protected = sp.Sheet.Value;
-            if (sp.Password != null) ws.Protection.PasswordHash = sp.Password.Value;
+
+            var algorithmName = sp.AlgorithmName?.Value ?? string.Empty;
+            if (String.IsNullOrEmpty(algorithmName))
+            {
+                ws.Protection.PasswordHash = sp.Password?.Value ?? string.Empty;
+            }
+            else
+            {
+                var hashValue = sp.HashValue?.Value ?? string.Empty;
+                var saltValue = sp.SaltValue?.Value ?? string.Empty;
+                // Continue for now.
+            }
             if (sp.FormatCells != null) ws.Protection.FormatCells = !sp.FormatCells.Value;
             if (sp.FormatColumns != null) ws.Protection.FormatColumns = !sp.FormatColumns.Value;
             if (sp.FormatRows != null) ws.Protection.FormatRows = !sp.FormatRows.Value;
diff --git a/ClosedXML_Tests/Excel/Worksheets/XLSheetProtectionTests.cs b/ClosedXML_Tests/Excel/Worksheets/XLSheetProtectionTests.cs
new file mode 100644
index 0000000..b74eaff
--- /dev/null
+++ b/ClosedXML_Tests/Excel/Worksheets/XLSheetProtectionTests.cs
@@ -0,0 +1,40 @@
+using ClosedXML.Excel;
+using NUnit.Framework;
+using System;
+
+namespace ClosedXML_Tests.Excel.Worksheets
+{
+    [TestFixture]
+    public class XLSheetProtectionTests
+    {
+        [Test]
+        public void TestUnprotectWorksheetWithNoPassword()
+        {
+            using (var stream = TestHelper.GetStreamFromResource(TestHelper.GetResourcePath(@"Misc\SHA512PasswordProtection.xlsx")))
+            using (var wb = new XLWorkbook(stream))
+            {
+                var ws = wb.Worksheet("Sheet1");
+                Assert.IsTrue(ws.Protection.Protected);
+                ws.Unprotect();
+                Assert.IsFalse(ws.Protection.Protected);
+            }
+        }
+
+        [Test]
+        public void TestWorksheetWithSHA512Protection()
+        {
+            using (var stream = TestHelper.GetStreamFromResource(TestHelper.GetResourcePath(@"Misc\SHA512PasswordProtection.xlsx")))
+            using (var wb = new XLWorkbook(stream))
+            {
+                var ws = wb.Worksheet("Sheet2");
+                Assert.IsTrue(ws.Protection.Protected);
+                // Protected with SHA-512 password - not yet supported.
+                Assert.Throws<ArgumentException>(() => ws.Unprotect());
+
+                // Protected with SHA-512 password - not yet supported.
+                Assert.Throws<ArgumentException>(() => ws.Unprotect("abc"));
+                Assert.IsTrue(ws.Protection.Protected);
+            }
+        }
+    }
+}
diff --git a/ClosedXML_Tests/Resource/Misc/SHA512PasswordProtection.xlsx b/ClosedXML_Tests/Resource/Misc/SHA512PasswordProtection.xlsx
new file mode 100644
index 0000000..61bf9c3
--- /dev/null
+++ b/ClosedXML_Tests/Resource/Misc/SHA512PasswordProtection.xlsx
Binary files differ