1 files changed, 7 insertions, 11 deletions
diff --git a/crypto/src/crypto/engines/AesEngine.cs b/crypto/src/crypto/engines/AesEngine.cs
index 8ccadf1bf..914550d6d 100644
--- a/crypto/src/crypto/engines/AesEngine.cs
+++ b/crypto/src/crypto/engines/AesEngine.cs
@@ -31,7 +31,7 @@ namespace Org.BouncyCastle.Crypto.Engines
     * This file contains the middle performance version with 2Kbytes of static tables for round precomputation.
     * </p>
     */
-    public class AesEngine
+    public sealed class AesEngine
         : IBlockCipher
     {
         // The S box
@@ -447,13 +447,9 @@ namespace Org.BouncyCastle.Crypto.Engines
         * @exception ArgumentException if the parameters argument is
         * inappropriate.
         */
-        public virtual void Init(
-            bool				forEncryption,
-            ICipherParameters	parameters)
+        public void Init(bool forEncryption, ICipherParameters parameters)
         {
-            KeyParameter keyParameter = parameters as KeyParameter;
-
-            if (keyParameter == null)
+            if (!(parameters is KeyParameter keyParameter))
                 throw new ArgumentException("invalid parameter passed to AES init - "
                     + Platform.GetTypeName(parameters));
 
@@ -463,17 +459,17 @@ namespace Org.BouncyCastle.Crypto.Engines
             this.s = Arrays.Clone(forEncryption ? S : Si);
         }
 
-        public virtual string AlgorithmName
+        public string AlgorithmName
         {
             get { return "AES"; }
         }
 
-        public virtual int GetBlockSize()
+        public int GetBlockSize()
         {
             return BLOCK_SIZE;
         }
 
-        public virtual int ProcessBlock(byte[] input, int inOff, byte[] output, int outOff)
+        public int ProcessBlock(byte[] input, int inOff, byte[] output, int outOff)
         {
             if (WorkingKey == null)
                 throw new InvalidOperationException("AES engine not initialised");
@@ -505,7 +501,7 @@ namespace Org.BouncyCastle.Crypto.Engines
         }
 
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
-        public virtual int ProcessBlock(ReadOnlySpan<byte> input, Span<byte> output)
+        public int ProcessBlock(ReadOnlySpan<byte> input, Span<byte> output)
         {
             if (WorkingKey == null)
                 throw new InvalidOperationException("AES engine not initialised");