Switched to BouncyCastle for MD5

README.md

@@ -19,6 +19,6 @@ Nevertheless, the performance on Sandy Bridge @2.8GHz is as follows:
 
 * If only phrases of at most 3 words are allowed, then it takes 2.5 seconds to find and check all anagrams; all relevant hashes are solved in first 0.4 seconds;
 
-* If phrases of 4 words are allowed as well, then it takes 70 seconds to find and check all anagrams; all hashes are solved in first 5 seconds;
+* If phrases of 4 words are allowed as well, then it takes 40 seconds to find and check all anagrams; all hashes are solved in first 3 seconds;
 
 For comparison, certain other solutions available on GitHub seem to require 3 hours to find all 3-word anagrams (i.e. this solution is faster by a factor of 4000 in 3-word case).

WhiteRabbit/Program.cs

@@ -5,8 +5,8 @@
     using System.Diagnostics;
     using System.Linq;
     using System.Numerics;
-    using System.Security.Cryptography;
     using System.Text;
+    using Org.BouncyCastle.Crypto.Digests;
 
     /// <summary>
     /// Main class
@@ -15,7 +15,7 @@
     {
         const string SourcePhrase = "poultry outwits ants";
 
-        const int MaxWordsInPhrase = 4;
+        const int MaxWordsInPhrase = 3;
 
         /// <summary>
         /// Main entry point
@@ -33,7 +33,7 @@
                 "665e5bcb0c20062fe8abaaf4628bb154",
             };
 
-            var expectedHashesAsVectors = new HashSet<Vector<byte>>(expectedHashes.Select(hash => new Vector<byte>(StringToByteArray(hash))));
+            var expectedHashesAsVectors = expectedHashes.Select(hash => new Vector<byte>(StringToByteArray(hash))).ToArray();
 
             foreach (var result in AddHashes(processor.GeneratePhrases(ReadInput())))
             {
@@ -58,16 +58,21 @@
 
         private static IEnumerable<Tuple<byte[], Vector<byte>>> AddHashes(IEnumerable<byte[]> input)
         {
-            using (MD5 hasher = MD5.Create())
+            foreach (var line in input)
             {
-                foreach (var line in input)
-                {
-                    var data = hasher.ComputeHash(line);
-                    yield return Tuple.Create(line, new Vector<byte>(data));
-                }
+                yield return Tuple.Create(line, ComputeHash(line));
             }
         }
 
+        private static Vector<byte> ComputeHash(byte[] input)
+        {
+            var digest = new MD5Digest();
+            digest.BlockUpdate(input, 0, input.Length);
+            byte[] hash = new byte[16];
+            digest.DoFinal(hash, 0);
+            return new Vector<byte>(hash);
+        }
+
         private static IEnumerable<byte[]> ReadInput()
         {
             string line;

WhiteRabbit/WhiteRabbit.csproj

@@ -34,6 +34,10 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="BouncyCastle.Crypto, Version=1.8.1.0, Culture=neutral, PublicKeyToken=0e99375e54769942">
+      <HintPath>..\packages\BouncyCastle.1.8.1\lib\BouncyCastle.Crypto.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Collections.Immutable, Version=1.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
       <HintPath>..\packages\System.Collections.Immutable.1.3.1\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>

WhiteRabbit/packages.config

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="BouncyCastle" version="1.8.1" targetFramework="net46" />
   <package id="System.Collections.Immutable" version="1.3.1" targetFramework="net46" />
   <package id="System.Numerics.Vectors" version="4.3.0" targetFramework="net46" />
 </packages>