VMPC refactoring

2 files changed, 70 insertions, 80 deletions

diff --git a/crypto/src/crypto/engines/VMPCEngine.cs b/crypto/src/crypto/engines/VMPCEngine.cs
index d8974b6ce..f34259248 100644
--- a/crypto/src/crypto/engines/VMPCEngine.cs
+++ b/crypto/src/crypto/engines/VMPCEngine.cs
@@ -97,16 +97,17 @@ namespace Org.BouncyCastle.Crypto.Engines
 
             for (int i = 0; i < len; i++)
             {
-                s = P[(s + P[n & 0xff]) & 0xff];
-                byte z = P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff];
+                byte pn = P[n];
+                s = P[(s + pn) & 0xff];
+                byte ps = P[s];
+                byte z = P[(P[ps] + 1) & 0xff];
                 // encryption
-                byte temp = P[n & 0xff];
-                P[n & 0xff] = P[s & 0xff];
-                P[s & 0xff] = temp;
-                n = (byte) ((n + 1) & 0xff);
+                P[n] = ps;
+                P[s] = pn;
+                n = (byte)(n + 1);
 
                 // xor
-                output[i + outOff] = (byte) (input[i + inOff] ^ z);
+                output[i + outOff] = (byte)(input[i + inOff] ^ z);
             }
         }
 
@@ -117,13 +118,14 @@ namespace Org.BouncyCastle.Crypto.Engines
 
             for (int i = 0; i < input.Length; i++)
             {
-                s = P[(s + P[n & 0xff]) & 0xff];
-                byte z = P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff];
+                byte pn = P[n];
+                s = P[(s + pn) & 0xff];
+                byte ps = P[s];
+                byte z = P[(P[ps] + 1) & 0xff];
                 // encryption
-                byte temp = P[n & 0xff];
-                P[n & 0xff] = P[s & 0xff];
-                P[s & 0xff] = temp;
-                n = (byte)((n + 1) & 0xff);
+                P[n] = ps;
+                P[s] = pn;
+                n = (byte)(n + 1);
 
                 // xor
                 output[i] = (byte)(input[i] ^ z);
diff --git a/crypto/src/crypto/prng/VMPCRandomGenerator.cs b/crypto/src/crypto/prng/VMPCRandomGenerator.cs
index 13b097789..92d163710 100644
--- a/crypto/src/crypto/prng/VMPCRandomGenerator.cs
+++ b/crypto/src/crypto/prng/VMPCRandomGenerator.cs
@@ -4,11 +4,9 @@ using Org.BouncyCastle.Crypto.Utilities;
 
 namespace Org.BouncyCastle.Crypto.Prng
 {
-    public class VmpcRandomGenerator
+    public sealed class VmpcRandomGenerator
         : IRandomGenerator 
     {
-        private byte n = 0;
-
         /// <remarks>
         /// Permutation generated by code:
         /// <code>
@@ -28,77 +26,61 @@ namespace Org.BouncyCastle.Crypto.Prng
         ///     P[s &amp; 0xff] = temp;
         /// } </code>
         /// </remarks>
-        private byte[] P =
+        private readonly byte[] P =
         {
-            (byte) 0xbb, (byte) 0x2c, (byte) 0x62, (byte) 0x7f, (byte) 0xb5, (byte) 0xaa, (byte) 0xd4,
-            (byte) 0x0d, (byte) 0x81, (byte) 0xfe, (byte) 0xb2, (byte) 0x82, (byte) 0xcb, (byte) 0xa0, (byte) 0xa1,
-            (byte) 0x08, (byte) 0x18, (byte) 0x71, (byte) 0x56, (byte) 0xe8, (byte) 0x49, (byte) 0x02, (byte) 0x10,
-            (byte) 0xc4, (byte) 0xde, (byte) 0x35, (byte) 0xa5, (byte) 0xec, (byte) 0x80, (byte) 0x12, (byte) 0xb8,
-            (byte) 0x69, (byte) 0xda, (byte) 0x2f, (byte) 0x75, (byte) 0xcc, (byte) 0xa2, (byte) 0x09, (byte) 0x36,
-            (byte) 0x03, (byte) 0x61, (byte) 0x2d, (byte) 0xfd, (byte) 0xe0, (byte) 0xdd, (byte) 0x05, (byte) 0x43,
-            (byte) 0x90, (byte) 0xad, (byte) 0xc8, (byte) 0xe1, (byte) 0xaf, (byte) 0x57, (byte) 0x9b, (byte) 0x4c,
-            (byte) 0xd8, (byte) 0x51, (byte) 0xae, (byte) 0x50, (byte) 0x85, (byte) 0x3c, (byte) 0x0a, (byte) 0xe4,
-            (byte) 0xf3, (byte) 0x9c, (byte) 0x26, (byte) 0x23, (byte) 0x53, (byte) 0xc9, (byte) 0x83, (byte) 0x97,
-            (byte) 0x46, (byte) 0xb1, (byte) 0x99, (byte) 0x64, (byte) 0x31, (byte) 0x77, (byte) 0xd5, (byte) 0x1d,
-            (byte) 0xd6, (byte) 0x78, (byte) 0xbd, (byte) 0x5e, (byte) 0xb0, (byte) 0x8a, (byte) 0x22, (byte) 0x38,
-            (byte) 0xf8, (byte) 0x68, (byte) 0x2b, (byte) 0x2a, (byte) 0xc5, (byte) 0xd3, (byte) 0xf7, (byte) 0xbc,
-            (byte) 0x6f, (byte) 0xdf, (byte) 0x04, (byte) 0xe5, (byte) 0x95, (byte) 0x3e, (byte) 0x25, (byte) 0x86,
-            (byte) 0xa6, (byte) 0x0b, (byte) 0x8f, (byte) 0xf1, (byte) 0x24, (byte) 0x0e, (byte) 0xd7, (byte) 0x40,
-            (byte) 0xb3, (byte) 0xcf, (byte) 0x7e, (byte) 0x06, (byte) 0x15, (byte) 0x9a, (byte) 0x4d, (byte) 0x1c,
-            (byte) 0xa3, (byte) 0xdb, (byte) 0x32, (byte) 0x92, (byte) 0x58, (byte) 0x11, (byte) 0x27, (byte) 0xf4,
-            (byte) 0x59, (byte) 0xd0, (byte) 0x4e, (byte) 0x6a, (byte) 0x17, (byte) 0x5b, (byte) 0xac, (byte) 0xff,
-            (byte) 0x07, (byte) 0xc0, (byte) 0x65, (byte) 0x79, (byte) 0xfc, (byte) 0xc7, (byte) 0xcd, (byte) 0x76,
-            (byte) 0x42, (byte) 0x5d, (byte) 0xe7, (byte) 0x3a, (byte) 0x34, (byte) 0x7a, (byte) 0x30, (byte) 0x28,
-            (byte) 0x0f, (byte) 0x73, (byte) 0x01, (byte) 0xf9, (byte) 0xd1, (byte) 0xd2, (byte) 0x19, (byte) 0xe9,
-            (byte) 0x91, (byte) 0xb9, (byte) 0x5a, (byte) 0xed, (byte) 0x41, (byte) 0x6d, (byte) 0xb4, (byte) 0xc3,
-            (byte) 0x9e, (byte) 0xbf, (byte) 0x63, (byte) 0xfa, (byte) 0x1f, (byte) 0x33, (byte) 0x60, (byte) 0x47,
-            (byte) 0x89, (byte) 0xf0, (byte) 0x96, (byte) 0x1a, (byte) 0x5f, (byte) 0x93, (byte) 0x3d, (byte) 0x37,
-            (byte) 0x4b, (byte) 0xd9, (byte) 0xa8, (byte) 0xc1, (byte) 0x1b, (byte) 0xf6, (byte) 0x39, (byte) 0x8b,
-            (byte) 0xb7, (byte) 0x0c, (byte) 0x20, (byte) 0xce, (byte) 0x88, (byte) 0x6e, (byte) 0xb6, (byte) 0x74,
-            (byte) 0x8e, (byte) 0x8d, (byte) 0x16, (byte) 0x29, (byte) 0xf2, (byte) 0x87, (byte) 0xf5, (byte) 0xeb,
-            (byte) 0x70, (byte) 0xe3, (byte) 0xfb, (byte) 0x55, (byte) 0x9f, (byte) 0xc6, (byte) 0x44, (byte) 0x4a,
-            (byte) 0x45, (byte) 0x7d, (byte) 0xe2, (byte) 0x6b, (byte) 0x5c, (byte) 0x6c, (byte) 0x66, (byte) 0xa9,
-            (byte) 0x8c, (byte) 0xee, (byte) 0x84, (byte) 0x13, (byte) 0xa7, (byte) 0x1e, (byte) 0x9d, (byte) 0xdc,
-            (byte) 0x67, (byte) 0x48, (byte) 0xba, (byte) 0x2e, (byte) 0xe6, (byte) 0xa4, (byte) 0xab, (byte) 0x7c,
-            (byte) 0x94, (byte) 0x00, (byte) 0x21, (byte) 0xef, (byte) 0xea, (byte) 0xbe, (byte) 0xca, (byte) 0x72,
-            (byte) 0x4f, (byte) 0x52, (byte) 0x98, (byte) 0x3f, (byte) 0xc2, (byte) 0x14, (byte) 0x7b, (byte) 0x3b,
-            (byte) 0x54
+            0xbb, 0x2c, 0x62, 0x7f, 0xb5, 0xaa, 0xd4, 0x0d, 0x81, 0xfe, 0xb2, 0x82, 0xcb, 0xa0, 0xa1, 0x08,
+            0x18, 0x71, 0x56, 0xe8, 0x49, 0x02, 0x10, 0xc4, 0xde, 0x35, 0xa5, 0xec, 0x80, 0x12, 0xb8, 0x69,
+            0xda, 0x2f, 0x75, 0xcc, 0xa2, 0x09, 0x36, 0x03, 0x61, 0x2d, 0xfd, 0xe0, 0xdd, 0x05, 0x43, 0x90,
+            0xad, 0xc8, 0xe1, 0xaf, 0x57, 0x9b, 0x4c, 0xd8, 0x51, 0xae, 0x50, 0x85, 0x3c, 0x0a, 0xe4, 0xf3,
+            0x9c, 0x26, 0x23, 0x53, 0xc9, 0x83, 0x97, 0x46, 0xb1, 0x99, 0x64, 0x31, 0x77, 0xd5, 0x1d, 0xd6,
+            0x78, 0xbd, 0x5e, 0xb0, 0x8a, 0x22, 0x38, 0xf8, 0x68, 0x2b, 0x2a, 0xc5, 0xd3, 0xf7, 0xbc, 0x6f,
+            0xdf, 0x04, 0xe5, 0x95, 0x3e, 0x25, 0x86, 0xa6, 0x0b, 0x8f, 0xf1, 0x24, 0x0e, 0xd7, 0x40, 0xb3,
+            0xcf, 0x7e, 0x06, 0x15, 0x9a, 0x4d, 0x1c, 0xa3, 0xdb, 0x32, 0x92, 0x58, 0x11, 0x27, 0xf4, 0x59,
+            0xd0, 0x4e, 0x6a, 0x17, 0x5b, 0xac, 0xff, 0x07, 0xc0, 0x65, 0x79, 0xfc, 0xc7, 0xcd, 0x76, 0x42,
+            0x5d, 0xe7, 0x3a, 0x34, 0x7a, 0x30, 0x28, 0x0f, 0x73, 0x01, 0xf9, 0xd1, 0xd2, 0x19, 0xe9, 0x91,
+            0xb9, 0x5a, 0xed, 0x41, 0x6d, 0xb4, 0xc3, 0x9e, 0xbf, 0x63, 0xfa, 0x1f, 0x33, 0x60, 0x47, 0x89,
+            0xf0, 0x96, 0x1a, 0x5f, 0x93, 0x3d, 0x37, 0x4b, 0xd9, 0xa8, 0xc1, 0x1b, 0xf6, 0x39, 0x8b, 0xb7,
+            0x0c, 0x20, 0xce, 0x88, 0x6e, 0xb6, 0x74, 0x8e, 0x8d, 0x16, 0x29, 0xf2, 0x87, 0xf5, 0xeb, 0x70,
+            0xe3, 0xfb, 0x55, 0x9f, 0xc6, 0x44, 0x4a, 0x45, 0x7d, 0xe2, 0x6b, 0x5c, 0x6c, 0x66, 0xa9, 0x8c,
+            0xee, 0x84, 0x13, 0xa7, 0x1e, 0x9d, 0xdc, 0x67, 0x48, 0xba, 0x2e, 0xe6, 0xa4, 0xab, 0x7c, 0x94,
+            0x00, 0x21, 0xef, 0xea, 0xbe, 0xca, 0x72, 0x4f, 0x52, 0x98, 0x3f, 0xc2, 0x14, 0x7b, 0x3b, 0x54,
         };
 
         /// <remarks>Value generated in the same way as <c>P</c>.</remarks>
-        private byte s = (byte) 0xbe;
+        private byte s = 0xbe;
+        private byte n = 0;
 
         public VmpcRandomGenerator()
         {
         }
 
-        public virtual void AddSeedMaterial(byte[] seed) 
+        public void AddSeedMaterial(byte[] seed) 
         {
             for (int m = 0; m < seed.Length; m++) 
             {
-                s = P[(s + P[n & 0xff] + seed[m]) & 0xff];
-                byte temp = P[n & 0xff];
-                P[n & 0xff] = P[s & 0xff];
-                P[s & 0xff] = temp;
-                n = (byte) ((n + 1) & 0xff);
+                byte pn = P[n];
+                s = P[(s + pn + seed[m]) & 0xff];
+                P[n] = P[s];
+                P[s] = pn;
+                n = (byte)(n + 1);
             }
         }
 
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
-        public virtual void AddSeedMaterial(ReadOnlySpan<byte> seed)
+        public void AddSeedMaterial(ReadOnlySpan<byte> seed)
         {
             for (int m = 0; m < seed.Length; m++)
             {
-                s = P[(s + P[n & 0xff] + seed[m]) & 0xff];
-                byte temp = P[n & 0xff];
-                P[n & 0xff] = P[s & 0xff];
-                P[s & 0xff] = temp;
-                n = (byte)((n + 1) & 0xff);
+                byte pn = P[n];
+                s = P[(s + pn + seed[m]) & 0xff];
+                P[n] = P[s];
+                P[s] = pn;
+                n = (byte)(n + 1);
             }
         }
 #endif
 
-        public virtual void AddSeedMaterial(long seed) 
+        public void AddSeedMaterial(long seed) 
         {
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
             Span<byte> bytes = stackalloc byte[8];
@@ -109,41 +91,47 @@ namespace Org.BouncyCastle.Crypto.Prng
 #endif
         }
 
-        public virtual void NextBytes(byte[] bytes) 
+        public void NextBytes(byte[] bytes) 
         {
             NextBytes(bytes, 0, bytes.Length);
         }
 
-        public virtual void NextBytes(byte[] bytes, int start, int len) 
+        public void NextBytes(byte[] bytes, int start, int len) 
         {
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+            NextBytes(bytes.AsSpan(start, len));
+#else
             lock (P) 
             {
                 int end = start + len;
                 for (int i = start; i != end; i++) 
                 {
-                    s = P[(s + P[n & 0xff]) & 0xff];
-                    bytes[i] = P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff];
-                    byte temp = P[n & 0xff];
-                    P[n & 0xff] = P[s & 0xff];
-                    P[s & 0xff] = temp;
-                    n = (byte) ((n + 1) & 0xff);
+                    byte pn = P[n];
+                    s = P[(s + pn) & 0xFF];
+                    byte ps = P[s];
+                    bytes[i] = P[(P[ps] + 1) & 0xFF];
+                    P[s] = pn;
+                    P[n] = ps;
+                    n = (byte)(n + 1);
                 }
             }
+#endif
         }
 
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
-        public virtual void NextBytes(Span<byte> bytes)
+        public void NextBytes(Span<byte> bytes)
         {
             lock (P) 
             {
-                for (int i = 0; i != bytes.Length; i++) 
+                for (int i = 0; i < bytes.Length; ++i) 
                 {
-                    s = P[(s + P[n & 0xff]) & 0xff];
-                    bytes[i] = P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff];
-                    byte temp = P[n & 0xff];
-                    P[n & 0xff] = P[s & 0xff];
-                    P[s & 0xff] = temp;
-                    n = (byte) ((n + 1) & 0xff);
+                    byte pn = P[n];
+                    s = P[(s + pn) & 0xFF];
+                    byte ps = P[s];
+                    bytes[i] = P[(P[ps] + 1) & 0xFF];
+                    P[s] = pn;
+                    P[n] = ps;
+                    n = (byte)(n + 1);
                 }
             }
         }