Memory optimization #39

src/Standard.Licensing.sln

@@ -4,7 +4,7 @@ VisualStudioVersion = 17.8.34330.188
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Standard.Licensing", "Standard.Licensing\Standard.Licensing.csproj", "{C658755A-2F60-430B-A41E-9C11C817B909}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Standard.Licensing.Tests", "Standard.Licensing.Tests\Standard.Licensing.Tests.csproj", "{3BF56CDC-AA67-4BBC-A7F6-422920E0E2F9}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Standard.Licensing.Tests", "Standard.Licensing.Tests\Standard.Licensing.Tests.csproj", "{3BF56CDC-AA67-4BBC-A7F6-422920E0E2F9}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

src/Standard.Licensing/License.cs

@@ -42,6 +42,12 @@ public class License
     {
         private readonly XElement xmlData;
         private readonly string signatureAlgorithm = X9ObjectIdentifiers.ECDsaWithSha512.Id;
+        private static XmlReaderSettings defaultXmlReaderSettings = new XmlReaderSettings
+        {
+            IgnoreWhitespace = true, // Ignore unnecessary whitespace nodes
+            IgnoreComments = true,   // Skip comment nodes to reduce processing
+            IgnoreProcessingInstructions = true // Skip processing instructions
+        };
 
         /// <summary>
         /// Initializes a new instance of the <see cref="License"/> class.
@@ -279,7 +285,12 @@ public static License Load(string xmlString)
         /// <returns>A <see cref="License"/> populated from the <see cref="Stream"/> that contains XML.</returns>
         public static License Load(Stream stream)
         {
-            return new License(XElement.Load(stream, LoadOptions.None));
+            // Use XmlReader for efficient XML parsing
+            using (var reader = XmlReader.Create(stream, defaultXmlReaderSettings))
+            {
+                var xmlData = XElement.Load(reader);
+                return new License(xmlData);
+            }
         }
 
         /// <summary>
@@ -301,7 +312,9 @@ public static License Load(TextReader reader)
         /// <returns>A <see cref="License"/> populated from the <see cref="TextReader"/> that contains XML.</returns>
         public static License Load(XmlReader reader)
         {
-            return new License(XElement.Load(reader, LoadOptions.None));
+            // Directly load the XML from the XmlReader
+            var xmlData = XElement.Load(reader);
+            return new License(xmlData);
         }
 
         /// <summary>
@@ -311,7 +324,11 @@ public static License Load(XmlReader reader)
         /// <see cref="License"/> will be written to.</param>
         public void Save(Stream stream)
         {
-            xmlData.Save(stream);
+            // Use XmlWriter for efficient XML writing
+            using (var writer = XmlWriter.Create(stream, new XmlWriterSettings { Indent = true }))
+            {
+                xmlData.WriteTo(writer);
+            }
         }
 
         /// <summary>
@@ -321,7 +338,10 @@ public void Save(Stream stream)
         /// <see cref="License"/> will be written to.</param>
         public void Save(TextWriter textWriter)
         {
-            xmlData.Save(textWriter);
+            using (var writer = XmlWriter.Create(textWriter, new XmlWriterSettings { Indent = true }))
+            {
+                xmlData.WriteTo(writer);
+            }
         }
 
         /// <summary>

src/Standard.Licensing/Security/Cryptography/KeyFactory.cs

@@ -24,10 +24,15 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 using Org.BouncyCastle.Asn1.Pkcs;
-using Org.BouncyCastle.Crypto;
-using Org.BouncyCastle.Security;
 using Org.BouncyCastle.X509;
 using System;
+using System.Buffers;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Security;
+
+#if NET6_0_OR_GREATER
+using System.Security.Cryptography; // Use native cryptography in .NET 6.0+
+#endif
 
 namespace Standard.Licensing.Security.Cryptography
 {
@@ -43,14 +48,30 @@ internal static class KeyFactory
         /// <returns>The encrypted private key.</returns>
         public static string ToEncryptedPrivateKeyString(AsymmetricKeyParameter key, string passPhrase)
         {
-            var salt = new byte[16];
-            var secureRandom = SecureRandom.GetInstance("SHA256PRNG");
-            secureRandom.SetSeed(secureRandom.GenerateSeed(16)); //See Bug #135
-            secureRandom.NextBytes(salt);
+            // Rent a buffer for the salt (16 bytes for the salt)
+            var salt = ArrayPool<byte>.Shared.Rent(16);
 
-            return
-                Convert.ToBase64String(PrivateKeyFactory.EncryptKey(keyEncryptionAlgorithm, passPhrase.ToCharArray(),
-                                                                    salt, 10, key));
+            try
+            {
+#if NET6_0_OR_GREATER
+                // Use built-in cryptography (e.g., RNGCryptoServiceProvider) in .NET 6.0+
+                RandomNumberGenerator.Fill(salt.AsSpan(0, 16));
+#else
+                // Use BouncyCastle for .NET Standard 2.0 or other versions
+                var secureRandom = SecureRandom.GetInstance("SHA256PRNG");
+                secureRandom.SetSeed(secureRandom.GenerateSeed(16)); // Seed generation
+                secureRandom.NextBytes(salt, 0, 16);
+#endif
+                // Encrypt the key (BouncyCastle library used for all versions)
+                var encryptedKey = PrivateKeyFactory.EncryptKey(keyEncryptionAlgorithm, passPhrase.ToCharArray(), salt, 10, key);
+
+                return Convert.ToBase64String(encryptedKey);
+            }
+            finally
+            {
+                // Return the rented buffer to the pool
+                ArrayPool<byte>.Shared.Return(salt);
+            }
         }
 
         /// <summary>

src/Standard.Licensing/Standard.Licensing.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>net8.0;net6.0;netstandard2.0;net461</TargetFrameworks>
@@ -47,6 +47,7 @@ v1.1.9
 
   <ItemGroup>
     <PackageReference Include="BouncyCastle.Cryptography" Version="2.4.0" />
+    <PackageReference Include="System.Buffers" Version="4.5.1" />
   </ItemGroup>
 
 </Project>