Refactoring in Pqc.Crypto.Lms

4 files changed, 28 insertions, 37 deletions

diff --git a/crypto/src/pqc/crypto/lms/HSS.cs b/crypto/src/pqc/crypto/lms/HSS.cs
index 9c21198e4..317ee89f5 100644
--- a/crypto/src/pqc/crypto/lms/HSS.cs
+++ b/crypto/src/pqc/crypto/lms/HSS.cs
@@ -39,17 +39,19 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
                         0,
                         I,
                         1 << lms.LMSigParameters.H,
-                        rootSeed);
+                        rootSeed,
+                        isPlaceholder: false);
                 }
                 else
                 {
-                    keys[t] = new PlaceholderLMSPrivateKey(
+                    keys[t] = new LmsPrivateKeyParameters(
                         lms.LMSigParameters,
                         lms.LMOtsParameters,
                         -1,
                         zero,
                         1 << lms.LMSigParameters.H,
-                        zero);
+                        zero,
+                        isPlaceholder: true);
                 }
                 hssKeyMaxIndex <<= lms.LMSigParameters.H;
             }
@@ -196,25 +198,5 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
             }
             return Lms.VerifySignature(key, sigList[Nspk], message);
         }
-
-        private class PlaceholderLMSPrivateKey
-            : LmsPrivateKeyParameters
-        {
-            internal PlaceholderLMSPrivateKey(LMSigParameters lmsParameter, LMOtsParameters otsParameters, int q,
-                byte[] I, int maxQ, byte[] masterSecret)
-                : base(lmsParameter, otsParameters, q, I, maxQ, masterSecret)
-            {
-            }
-
-            internal override LMOtsPrivateKey GetNextOtsPrivateKey()
-            {
-                throw new Exception("placeholder only");
-            }
-
-            public override LmsPublicKeyParameters GetPublicKey()
-            {
-                throw new Exception("placeholder only");
-            }
-        }
     }
 }
diff --git a/crypto/src/pqc/crypto/lms/LMSKeyParameters.cs b/crypto/src/pqc/crypto/lms/LMSKeyParameters.cs
index b35ba36c4..aaddfb823 100644
--- a/crypto/src/pqc/crypto/lms/LMSKeyParameters.cs
+++ b/crypto/src/pqc/crypto/lms/LMSKeyParameters.cs
@@ -6,7 +6,7 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
     public abstract class LmsKeyParameters
         : AsymmetricKeyParameter, IEncodable
     {
-        protected LmsKeyParameters(bool isPrivateKey)
+        internal LmsKeyParameters(bool isPrivateKey)
             : base(isPrivateKey)
         {
         }
diff --git a/crypto/src/pqc/crypto/lms/LMSPrivateKeyParameters.cs b/crypto/src/pqc/crypto/lms/LMSPrivateKeyParameters.cs
index 25ca81938..dcdeb7ab5 100644
--- a/crypto/src/pqc/crypto/lms/LMSPrivateKeyParameters.cs
+++ b/crypto/src/pqc/crypto/lms/LMSPrivateKeyParameters.cs
@@ -9,7 +9,7 @@ using Org.BouncyCastle.Utilities.IO;
 
 namespace Org.BouncyCastle.Pqc.Crypto.Lms
 {
-    public class LmsPrivateKeyParameters
+    public sealed class LmsPrivateKeyParameters
         : LmsKeyParameters, ILmsContextBasedSigner
     {
         private static CacheKey T1 = new CacheKey(1);
@@ -34,6 +34,7 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
         private IDigest tDigest;
 
         private int q;
+        private readonly bool m_isPlaceholder;
 
         //
         // These are not final because they can be generated.
@@ -41,9 +42,14 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
         //
         private LmsPublicKeyParameters publicKey;
 
-
         public LmsPrivateKeyParameters(LMSigParameters lmsParameter, LMOtsParameters otsParameters, int q, byte[] I,
             int maxQ, byte[] masterSecret)
+            : this(lmsParameter, otsParameters, q, I, maxQ, masterSecret, false)
+        {
+        }
+
+        internal LmsPrivateKeyParameters(LMSigParameters lmsParameter, LMOtsParameters otsParameters, int q, byte[] I,
+            int maxQ, byte[] masterSecret, bool isPlaceholder)
             : base(true)
         {
             this.parameters = lmsParameter;
@@ -55,6 +61,7 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
             this.maxCacheR = 1 << (parameters.H + 1);
             this.tCache = new Dictionary<CacheKey, byte[]>();
             this.tDigest = DigestUtilities.GetDigest(lmsParameter.DigestOid);
+            this.m_isPlaceholder = isPlaceholder;
         }
 
         private LmsPrivateKeyParameters(LmsPrivateKeyParameters parent, int q, int maxQ)
@@ -203,8 +210,11 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
             }
         }
 
-        internal virtual LMOtsPrivateKey GetNextOtsPrivateKey()
+        internal LMOtsPrivateKey GetNextOtsPrivateKey()
         {
+            if (m_isPlaceholder)
+                throw new Exception("placeholder only");
+
             lock (this)
             {
                 if (q >= maxQ)
@@ -264,8 +274,11 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
             return maxQ - q;
         }
 
-        public virtual LmsPublicKeyParameters GetPublicKey()
+        public LmsPublicKeyParameters GetPublicKey()
         {
+            if (m_isPlaceholder)
+                throw new Exception("placeholder only");
+
             lock (this)
             {
                 if (publicKey == null)
@@ -276,7 +289,7 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
             }
         }
 
-        byte[] FindT(int r)
+        internal byte[] FindT(int r)
         {
             if (r < maxCacheR)
             {
@@ -290,14 +303,10 @@ namespace Org.BouncyCastle.Pqc.Crypto.Lms
         {
             lock (tCache)
             {
-                byte[] t;
-                if (!tCache.TryGetValue(key, out t))
-                {
-                    t = CalcT(key.index);
-                    tCache[key] = t;
-                }
+                if (tCache.TryGetValue(key, out byte[] t))
+                    return t;
 
-                return t;
+                return tCache[key] = CalcT(key.index);
             }
         }
 
diff --git a/crypto/src/pqc/crypto/lms/LMSPublicKeyParameters.cs b/crypto/src/pqc/crypto/lms/LMSPublicKeyParameters.cs
index fa12b47c3..f8d0970af 100644
--- a/crypto/src/pqc/crypto/lms/LMSPublicKeyParameters.cs
+++ b/crypto/src/pqc/crypto/lms/LMSPublicKeyParameters.cs
@@ -6,7 +6,7 @@ using Org.BouncyCastle.Utilities.IO;
 
 namespace Org.BouncyCastle.Pqc.Crypto.Lms
 {
-    public class LmsPublicKeyParameters
+    public sealed class LmsPublicKeyParameters
         : LmsKeyParameters, ILmsContextBasedVerifier
     {
         private LMSigParameters parameterSet;