Security-54.tar.gz

[apple/security.git] / SecurityServer / entropy.h

diff --git a/SecurityServer/entropy.h b/SecurityServer/entropy.h
new file mode 100644 (file)
index 0000000..7f5e348
--- /dev/null
+++ b/SecurityServer/entropy.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
+ * 
+ * The contents of this file constitute Original Code as defined in and are
+ * subject to the Apple Public Source License Version 1.2 (the 'License').
+ * You may not use this file except in compliance with the License. Please obtain
+ * a copy of the License at http://www.apple.com/publicsource and read it before
+ * using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
+ * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
+ * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
+ * specific language governing rights and limitations under the License.
+ */
+
+
+//
+// yarrowseed - periodical to collect and seed entropy into /dev/random
+//
+#ifndef _H_ENTROPY
+#define _H_ENTROPY
+
+#include <Security/machserver.h>
+#include <Security/timeflow.h>
+#include <Security/devrandom.h>
+
+using namespace Security;
+using MachPlusPlus::MachServer;
+
+
+//
+// A (one-off) timer object that manages system entropy
+//
+class EntropyManager : public MachServer::Timer, private DevRandomGenerator {
+    // all the parameters you ever (should) want to change :-)
+    static const int collectInterval = 600; // collect every 10 minutes
+    static const int updateInterval = 3600; // update file every hour
+    static const int timingsToCollect = 40; // how many timings?
+
+public:
+       EntropyManager(MachPlusPlus::MachServer &srv, const char *entropyFile);
+               
+       void action();
+    
+       MachPlusPlus::MachServer        &server;                // to which we do setTimer()
+    
+private:
+    string mEntropyFilePath;                   // absolute path to entropy file
+    Time::Absolute mNextUpdate;                        // next time for entropy file update
+    
+    void collectEntropy();                             // collect system timings and seed RNG
+    void updateEntropyFile();                  // update entropy file from RNG if it's time
+    
+    static const size_t entropyFileSize = 20;  // bytes (effectively one SHA-1 worth)
+};
+
+#endif //_H_ENTROPY