Options to set AES threadlevel

Duplicati/Library/Encryption/AESEncryption.cs

@@ -31,6 +31,12 @@ namespace Duplicati.Library.Encryption
     /// </summary>
     public class AESEncryption : EncryptionBase
     {
+
+        /// <summary>
+        /// The commandline option supplied if an explicit thread level should be set (--aes-set-threadlevel)
+        /// </summary>
+        private const string COMMANDLINE_SET_THREADLEVEL = "aes-set-threadlevel";
+
         /// <summary>
         /// The key used to encrypt the data
         /// </summary>
@@ -41,6 +47,11 @@ namespace Duplicati.Library.Encryption
         /// </summary>
         private static long m_cachedsizeoverhead = -1;
 
+        /// <summary>
+        /// The thread level to pass to SharpAESCrypt. 0 for default.
+        /// </summary>
+        private static int m_usethreadlevel = 0;
+
         /// <summary>
         /// Default constructor, used to read file extension and supported commands
         /// </summary>
@@ -56,8 +67,22 @@ namespace Duplicati.Library.Encryption
         {
             if(string.IsNullOrEmpty(passphrase))
                 throw new ArgumentException(Strings.AESEncryption.EmptyKeyError, "passphrase");
-                
+
             m_key = passphrase;
+
+            string strTL;
+            if (options != null && options.TryGetValue(COMMANDLINE_SET_THREADLEVEL, out strTL))
+            {
+                int useTL;
+                if (int.TryParse(strTL, out useTL))
+                {
+                    // finally set thread level in a range of 0 (default) to 4
+                    m_usethreadlevel = Math.Max(0, (Math.Min(4, useTL)));
+                }
+            }
+
+
+
         }
 
         #region IEncryption Members
@@ -107,7 +132,9 @@ namespace Duplicati.Library.Encryption
         /// <returns>An encrypted stream that can be written to</returns>
         public override Stream Encrypt(Stream input)
         {
-            return new SharpAESCrypt.SharpAESCrypt(m_key, input, SharpAESCrypt.OperationMode.Encrypt);
+            var cryptoStream = new SharpAESCrypt.SharpAESCrypt(m_key, input, SharpAESCrypt.OperationMode.Encrypt);
+            if (m_usethreadlevel != 0) cryptoStream.MaxCryptoThreads = m_usethreadlevel;
+            return cryptoStream;
         }
 
         /// <summary>
@@ -117,7 +144,9 @@ namespace Duplicati.Library.Encryption
         /// <returns>The unencrypted stream</returns>
         public override Stream Decrypt(Stream input)
         {
-            return new SharpAESCrypt.SharpAESCrypt(m_key, input, SharpAESCrypt.OperationMode.Decrypt);
+            var cryptoStream = new SharpAESCrypt.SharpAESCrypt(m_key, input, SharpAESCrypt.OperationMode.Decrypt);
+            if (m_usethreadlevel != 0) cryptoStream.MaxCryptoThreads = m_usethreadlevel;
+            return cryptoStream;
         }
 
         /// <summary>
@@ -129,6 +158,7 @@ namespace Duplicati.Library.Encryption
             get
             {
                 return new List<ICommandLineArgument>(new ICommandLineArgument[] {
+                    new CommandLineArgument(COMMANDLINE_SET_THREADLEVEL, CommandLineArgument.ArgumentType.String, Strings.AESEncryption.AessetthreadlevelShort, Strings.AESEncryption.AessetthreadlevelLong),
                 });
             }
         }

Duplicati/Library/Encryption/Strings.cs

@@ -4,6 +4,8 @@ namespace Duplicati.Library.Encryption.Strings {
         public static string Description_v2 { get { return LC.L(@"This module encrypts all files in the same way that AESCrypt does, using 256 bit AES encryption."); } }
         public static string DisplayName { get { return LC.L(@"AES-256 encryption, built in"); } }
         public static string EmptyKeyError { get { return LC.L(@"Blank or empty passphrase not allowed"); } }
+        public static string AessetthreadlevelLong { get { return LC.L(@"Use this option to set the thread level allowed for AES crypt operations. Valid values are 0 (uses default), or from 1 (no multithreading) to 4 (max. multithreading)"); } }
+        public static string AessetthreadlevelShort { get { return LC.L(@"Set thread level utilized for crypting (0-4)"); } }
     }
     internal static class EncryptionBase {
         public static string DecryptionError(string message) { return LC.L(@"Failed to decrypt data (invalid passphrase?): {0}", message); }