2 // Mono.Security.Protocol.Ntlm.ChallengeResponse
3 // Implements Challenge Response for NTLM v1
6 // Sebastien Pouliot <sebastien@ximian.com>
8 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
9 // (C) 2004 Novell (http://www.novell.com)
12 // a. NTLM Authentication Scheme for HTTP, Ronald Tschalär
13 // http://www.innovation.ch/java/ntlm.html
14 // b. The NTLM Authentication Protocol, Copyright © 2003 Eric Glass
15 // http://davenport.sourceforge.net/ntlm.html
19 // Permission is hereby granted, free of charge, to any person obtaining
20 // a copy of this software and associated documentation files (the
21 // "Software"), to deal in the Software without restriction, including
22 // without limitation the rights to use, copy, modify, merge, publish,
23 // distribute, sublicense, and/or sell copies of the Software, and to
24 // permit persons to whom the Software is furnished to do so, subject to
25 // the following conditions:
27 // The above copyright notice and this permission notice shall be
28 // included in all copies or substantial portions of the Software.
30 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
31 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
32 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
33 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
34 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
35 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
36 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
40 using System.Globalization;
41 using System.Security.Cryptography;
44 using Mono.Security.Cryptography;
46 namespace Mono.Security.Protocol.Ntlm {
48 [Obsolete (Type3Message.LegacyAPIWarning)]
49 public class ChallengeResponse : IDisposable {
51 static private byte[] magic = { 0x4B, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25 };
53 // This is the pre-encrypted magic value with a null DES key (0xAAD3B435B51404EE)
54 // Ref: http://packetstormsecurity.nl/Crackers/NT/l0phtcrack/l0phtcrack2.5-readme.html
55 static private byte[] nullEncMagic = { 0xAA, 0xD3, 0xB4, 0x35, 0xB5, 0x14, 0x04, 0xEE };
57 private bool _disposed;
58 private byte[] _challenge;
59 private byte[] _lmpwd;
60 private byte[] _ntpwd;
64 public ChallengeResponse ()
67 _lmpwd = new byte [21];
68 _ntpwd = new byte [21];
71 public ChallengeResponse (string password, byte[] challenge) : this ()
74 Challenge = challenge;
85 public string Password {
89 throw new ObjectDisposedException ("too late");
91 // create Lan Manager password
92 DES des = DES.Create ();
93 des.Mode = CipherMode.ECB;
94 ICryptoTransform ct = null;
96 // Note: In .NET DES cannot accept a weak key
97 // this can happen for a null password
98 if ((value == null) || (value.Length < 1)) {
99 Buffer.BlockCopy (nullEncMagic, 0, _lmpwd, 0, 8);
102 des.Key = PasswordToKey (value, 0);
103 ct = des.CreateEncryptor ();
104 ct.TransformBlock (magic, 0, 8, _lmpwd, 0);
107 // and if a password has less than 8 characters
108 if ((value == null) || (value.Length < 8)) {
109 Buffer.BlockCopy (nullEncMagic, 0, _lmpwd, 8, 8);
112 des.Key = PasswordToKey (value, 7);
113 ct = des.CreateEncryptor ();
114 ct.TransformBlock (magic, 0, 8, _lmpwd, 8);
117 // create NT password
118 MD4 md4 = MD4.Create ();
119 byte[] data = ((value == null) ? (new byte [0]) : (Encoding.Unicode.GetBytes (value)));
120 byte[] hash = md4.ComputeHash (data);
121 Buffer.BlockCopy (hash, 0, _ntpwd, 0, 16);
124 Array.Clear (data, 0, data.Length);
125 Array.Clear (hash, 0, hash.Length);
130 public byte[] Challenge {
134 throw new ArgumentNullException ("Challenge");
136 throw new ObjectDisposedException ("too late");
137 // we don't want the caller to modify the value afterward
138 _challenge = (byte[]) value.Clone ();
145 throw new ObjectDisposedException ("too late");
147 return GetResponse (_lmpwd);
154 throw new ObjectDisposedException ("too late");
156 return GetResponse (_ntpwd);
160 // IDisposable method
162 public void Dispose ()
165 GC.SuppressFinalize (this);
168 private void Dispose (bool disposing)
172 Array.Clear (_lmpwd, 0, _lmpwd.Length);
173 Array.Clear (_ntpwd, 0, _ntpwd.Length);
174 if (_challenge != null)
175 Array.Clear (_challenge, 0, _challenge.Length);
182 private byte[] GetResponse (byte[] pwd)
184 byte[] response = new byte [24];
185 DES des = DES.Create ();
186 des.Mode = CipherMode.ECB;
187 des.Key = PrepareDESKey (pwd, 0);
188 ICryptoTransform ct = des.CreateEncryptor ();
189 ct.TransformBlock (_challenge, 0, 8, response, 0);
190 des.Key = PrepareDESKey (pwd, 7);
191 ct = des.CreateEncryptor ();
192 ct.TransformBlock (_challenge, 0, 8, response, 8);
193 des.Key = PrepareDESKey (pwd, 14);
194 ct = des.CreateEncryptor ();
195 ct.TransformBlock (_challenge, 0, 8, response, 16);
199 private byte[] PrepareDESKey (byte[] key56bits, int position)
201 // convert to 8 bytes
202 byte[] key = new byte [8];
203 key [0] = key56bits [position];
204 key [1] = (byte) ((key56bits [position] << 7) | (key56bits [position + 1] >> 1));
205 key [2] = (byte) ((key56bits [position + 1] << 6) | (key56bits [position + 2] >> 2));
206 key [3] = (byte) ((key56bits [position + 2] << 5) | (key56bits [position + 3] >> 3));
207 key [4] = (byte) ((key56bits [position + 3] << 4) | (key56bits [position + 4] >> 4));
208 key [5] = (byte) ((key56bits [position + 4] << 3) | (key56bits [position + 5] >> 5));
209 key [6] = (byte) ((key56bits [position + 5] << 2) | (key56bits [position + 6] >> 6));
210 key [7] = (byte) (key56bits [position + 6] << 1);
214 private byte[] PasswordToKey (string password, int position)
216 byte[] key7 = new byte [7];
217 int len = System.Math.Min (password.Length - position, 7);
218 Encoding.ASCII.GetBytes (password.ToUpper (CultureInfo.CurrentCulture), position, len, key7, 0);
219 byte[] key8 = PrepareDESKey (key7, 0);
220 // cleanup intermediate key material
221 Array.Clear (key7, 0, key7.Length);