5 // Duco Fijma (duco@lorentz.xs4all.nl)
6 // Sebastien Pouliot (sebastien@ximian.com)
7 // Jb Evain (jbevain@novell.com)
8 // Marek Safar (marek.safar@gmail.com)
10 // (C) 2002 Duco Fijma
11 // Copyright (C) 2004-2010 Novell, Inc (http://www.novell.com)
12 // Copyright 2012, 2014 Xamarin, Inc (http://www.xamarin.com)
14 // Permission is hereby granted, free of charge, to any person obtaining
15 // a copy of this software and associated documentation files (the
16 // "Software"), to deal in the Software without restriction, including
17 // without limitation the rights to use, copy, modify, merge, publish,
18 // distribute, sublicense, and/or sell copies of the Software, and to
19 // permit persons to whom the Software is furnished to do so, subject to
20 // the following conditions:
22 // The above copyright notice and this permission notice shall be
23 // included in all copies or substantial portions of the Software.
25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
36 using System.Security.Cryptography;
42 private static object _rngAccess = new object ();
43 private static RandomNumberGenerator _rng;
44 private static RandomNumberGenerator _fastRng;
46 public static Guid NewGuid ()
48 byte[] b = new byte [16];
49 // thread-safe access to the prng
52 _rng = RandomNumberGenerator.Create ();
56 Guid res = new Guid (b);
57 // Mask in Variant 1-0 in Bit[7..6]
58 res._d = (byte) ((res._d & 0x3fu) | 0x80u);
59 // Mask in Version 4 (random based Guid) in Bits[15..13]
60 res._c = (short) ((res._c & 0x0fffu) | 0x4000u);
65 // used in ModuleBuilder so mcs doesn't need to invoke
66 // CryptoConfig for simple assemblies.
67 internal static byte[] FastNewGuidArray ()
69 byte[] guid = new byte [16];
71 // thread-safe access to the prng
73 // if known, use preferred RNG
76 // else use hardcoded default RNG (bypassing CryptoConfig)
78 _fastRng = new RNGCryptoServiceProvider ();
79 _fastRng.GetBytes (guid);
82 // Mask in Variant 1-0 in Bit[7..6]
83 guid [8] = (byte) ((guid [8] & 0x3f) | 0x80);
84 // Mask in Version 4 (random based Guid) in Bits[15..13]
85 guid [7] = (byte) ((guid [7] & 0x0f) | 0x40);