2 // HMAC.cs: Generic HMAC inplementation
5 // Sebastien Pouliot <sebastien@ximian.com>
7 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
8 // Copyright (C) 2004-2005, 2007 Novell, Inc (http://www.novell.com)
10 // Permission is hereby granted, free of charge, to any person obtaining
11 // a copy of this software and associated documentation files (the
12 // "Software"), to deal in the Software without restriction, including
13 // without limitation the rights to use, copy, modify, merge, publish,
14 // distribute, sublicense, and/or sell copies of the Software, and to
15 // permit persons to whom the Software is furnished to do so, subject to
16 // the following conditions:
18 // The above copyright notice and this permission notice shall be
19 // included in all copies or substantial portions of the Software.
21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 using System.Runtime.InteropServices;
32 using Mono.Security.Cryptography;
34 namespace System.Security.Cryptography {
36 // Mostly copied from (internal) Mono.Security.Cryptography.HMACAlgorithm
39 // a. FIPS PUB 198: The Keyed-Hash Message Authentication Code (HMAC), 2002 March.
40 // http://csrc.nist.gov/publications/fips/fips198/fips-198a.pdf
41 // b. Internet RFC 2104, HMAC, Keyed-Hashing for Message Authentication
42 // (include C source for HMAC-MD5)
43 // http://www.ietf.org/rfc/rfc2104.txt
44 // c. IETF RFC2202: Test Cases for HMAC-MD5 and HMAC-SHA-1
45 // (include C source for HMAC-MD5 and HAMAC-SHA1)
46 // http://www.ietf.org/rfc/rfc2202.txt
47 // d. ANSI X9.71, Keyed Hash Message Authentication Code.
49 // http://webstore.ansi.org/ansidocstore/product.asp?sku=ANSI+X9%2E71%2D2000
52 public abstract class HMAC : KeyedHashAlgorithm {
54 private bool _disposed;
55 private string _hashName;
56 private HashAlgorithm _algo;
57 private BlockProcessor _block;
58 private int _blockSizeValue;
70 protected int BlockSizeValue {
71 get { return _blockSizeValue; }
72 set { _blockSizeValue = value; }
75 public string HashName {
76 get { return _hashName; }
79 _algo = HashAlgorithm.Create (_hashName);
83 public override byte[] Key {
84 get { return (byte[]) base.Key.Clone (); }
86 if ((value != null) && (value.Length > BlockSizeValue))
87 base.Key = _algo.ComputeHash (value);
89 base.Key = (byte[]) value.Clone();
93 internal BlockProcessor Block {
96 _block = new BlockProcessor (_algo, (BlockSizeValue >> 3));
103 private byte[] KeySetup (byte[] key, byte padding)
105 byte[] buf = new byte [BlockSizeValue];
107 for (int i = 0; i < key.Length; ++i)
108 buf [i] = (byte) ((byte) key [i] ^ padding);
110 for (int i = key.Length; i < BlockSizeValue; ++i)
116 protected override void Dispose (bool disposing)
119 base.Dispose (disposing);
123 protected override void HashCore (byte[] rgb, int ib, int cb)
126 throw new ObjectDisposedException ("HMACSHA1");
132 Block.Core (rgb, ib, cb);
135 protected override byte[] HashFinal ()
138 throw new ObjectDisposedException ("HMAC");
142 byte[] intermediate = _algo.Hash;
144 byte[] buf = KeySetup (Key, 0x5C);
146 _algo.TransformBlock (buf, 0, buf.Length, buf, 0);
147 _algo.TransformFinalBlock (intermediate, 0, intermediate.Length);
148 byte[] hash = _algo.Hash;
150 // zeroize sensitive data
151 Array.Clear (buf, 0, buf.Length);
152 Array.Clear (intermediate, 0, intermediate.Length);
156 public override void Initialize ()
159 throw new ObjectDisposedException ("HMAC");
163 byte[] buf = KeySetup (Key, 0x36);
167 Array.Clear (buf, 0, buf.Length);
172 public static new HMAC Create ()
174 return Create ("System.Security.Cryptography.HMAC");
177 public static new HMAC Create (string algorithmName)
179 return (HMAC) CryptoConfig.CreateFromName (algorithmName);