diff --git a/main/NPOI.Core.csproj b/main/NPOI.Core.csproj
index 7f80d4bb1..26a0530cf 100644
--- a/main/NPOI.Core.csproj
+++ b/main/NPOI.Core.csproj
@@ -23,7 +23,7 @@
     <PackageReference Include="Enums.NET" Version="4.0.1" />
     <PackageReference Include="MathNet.Numerics.Signed" Version="4.15.0" />
     <PackageReference Include="Microsoft.IO.RecyclableMemoryStream" Version="2.3.2" />
-    <PackageReference Include="Portable.BouncyCastle" Version="1.9.0" />
+    <PackageReference Include="BouncyCastle.Cryptography" Version="2.2.1" />
     <PackageReference Include="SharpZipLib" Version="1.3.3" />
     <PackageReference Include="SixLabors.Fonts" Version="1.0.0-beta19" />
     <PackageReference Include="SixLabors.ImageSharp" Version="2.1.4" />
diff --git a/main/POIFS/Crypt/Standard/StandardDecryptor.cs b/main/POIFS/Crypt/Standard/StandardDecryptor.cs
index 96feef9c6..bcd4434df 100644
--- a/main/POIFS/Crypt/Standard/StandardDecryptor.cs
+++ b/main/POIFS/Crypt/Standard/StandardDecryptor.cs
@@ -399,6 +399,28 @@ public void Reset()
         {
             
         }
+
+#if NET6_0_OR_GREATER
+        public int ProcessByte(byte input, Span<byte> output)
+        {
+            return 0;
+        }
+
+        public int ProcessBytes(ReadOnlySpan<byte> input, Span<byte> output)
+        {
+            return 0;
+        }
+
+        public int DoFinal(Span<byte> output)
+        {
+            return 0;
+        }
+
+        public int DoFinal(ReadOnlySpan<byte> input, Span<byte> output)
+        {
+            return 0;
+        }
+#endif
     }
     public class NullCipher : Cipher
     {