1 files changed, 72 insertions, 5 deletions
diff --git a/crypto/src/pqc/crypto/sike/SIKEParameters.cs b/crypto/src/pqc/crypto/sike/SIKEParameters.cs
index d18797067..07d2d77ef 100644
--- a/crypto/src/pqc/crypto/sike/SIKEParameters.cs
+++ b/crypto/src/pqc/crypto/sike/SIKEParameters.cs
@@ -1,10 +1,51 @@
 using System;
+using System.Runtime.ConstrainedExecution;
 
 namespace Org.BouncyCastle.Pqc.Crypto.Sike
 {
     [Obsolete("Will be removed")]
     public sealed class SikeParameters
     {
+        private class SikeP434Engine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(434, false, null);
+        }
+
+        private class SikeP503Engine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(503, false, null);
+        }
+
+        private class SikeP610Engine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(610, false, null);
+        }
+
+        private class SikeP751Engine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(751, false, null);
+        }
+
+        private class SikeP434CompressedEngine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(434, true, null);
+        }
+
+        private class SikeP503CompressedEngine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(503, true, null);
+        }
+
+        private class SikeP610CompressedEngine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(610, true, null);
+        }
+
+        private class SikeP751CompressedEngine
+        {
+            internal static readonly SikeEngine Instance = new SikeEngine(751, true, null);
+        }
+
         public static readonly SikeParameters sikep434 = new SikeParameters(434, false, "sikep434");
         public static readonly SikeParameters sikep503 = new SikeParameters(503, false, "sikep503");
         public static readonly SikeParameters sikep610 = new SikeParameters(610, false, "sikep610");
@@ -15,19 +56,45 @@ namespace Org.BouncyCastle.Pqc.Crypto.Sike
         public static readonly SikeParameters sikep610_compressed = new SikeParameters(610, true, "sikep610_compressed");
         public static readonly SikeParameters sikep751_compressed = new SikeParameters(751, true, "sikep751_compressed");
 
+        private readonly int ver;
+        private readonly bool isCompressed;
         private readonly string name;
-        private readonly SikeEngine engine;
 
-        public SikeParameters(int ver, bool isCompressed, string name)
+        private SikeParameters(int ver, bool isCompressed, string name)
         {
+            this.ver = ver;
+            this.isCompressed = isCompressed;
             this.name = name;
-            this.engine = new SikeEngine(ver, isCompressed, null);
         }
 
-        internal SikeEngine Engine => engine;
+        internal SikeEngine GetEngine()
+        {
+            if (isCompressed)
+            {
+                switch (ver)
+                {
+                case 434:   return SikeP434CompressedEngine.Instance;
+                case 503:   return SikeP503CompressedEngine.Instance;
+                case 610:   return SikeP610CompressedEngine.Instance;
+                case 751:   return SikeP751CompressedEngine.Instance;
+                default:    throw new InvalidOperationException();
+                }
+            }
+            else
+            {
+                switch (ver)
+                {
+                case 434:   return SikeP434Engine.Instance;
+                case 503:   return SikeP503Engine.Instance;
+                case 610:   return SikeP610Engine.Instance;
+                case 751:   return SikeP751Engine.Instance;
+                default:    throw new InvalidOperationException();
+                }
+            }
+        }
 
         public string Name => name;
 
-        public int DefaultKeySize => (int)this.engine.GetDefaultSessionKeySize();
+        public int DefaultKeySize => (int)GetEngine().GetDefaultSessionKeySize();
     }
 }