看好你的数据库连接字符串!
一般情况下，大多数人习惯于将数据库连接写在web.config上里面，理论上讲，将明文存放在该文件里面是安全的，因为web.config文件是不允许被客户端下载，但一旦该文件泄漏出去，哪怕是很短的时间，数据库都将承受巨大的危害，可能花上N年才充实起来的信息在很短时间里毁于一旦。这是任何程序绝对不应该出现的问题。有人用简单的对称加密来将数据库连接字符串的密文存放，但密钥一旦丢失，加密与否，形同虚设，那么如何保证连接字符串的安全性呢。下面这个类就完成这个功能，该类调用系统API，在不同的系统中对相同的连接串会生成不同的密文，即使非法获得该串，不能获得在服务器上的管理员权限，仍然没有能力知道数据库的真正所在。有人说，那服务器管理员权限也被盗用了呢？那盗用者还需要经过一系列复杂的跟踪和总结，来获得系统标识变量。这无疑又是一个难度，等到他真正破解了解该系统的时候，也许你早就在此之前，改正了服务器的配置和密码，还害得人家白忙活了一趟。够阴的！
呵呵
代码如下:
呵呵
代码如下:
1
using System;
2using System.Text;
3using System.Runtime.InteropServices;
4
5namespace JillZhang.Security
6
{
7
public enum Store
8
{
9 USE_NACHINE_STORE=1,USE_USER_STORE
10
};
11 public class DataProtector
12 {
13
14 [DllImport("Crypt32.dll",SetLastError=true,CharSet=System.Runtime.InteropServices.CharSet.Auto)]
15 private static extern bool CryptProtectData
16 (
17 ref DATA_BLOB pDataIn,
18 String szDataDecr,
19 ref DATA_BLOB pOptionEntropy,
20 IntPtr pvReserved,
21 ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
22 int dwFlags,
23 ref DATA_BLOB pDataOut
24 );
25
26 [DllImport("Crypt32.dll",SetLastError=true,CharSet=System.Runtime.InteropServices.CharSet.Auto)]
27 private static extern bool CryptUnprotectData
28 (
29 ref DATA_BLOB pDataIn,
30 String szDataDecr,
31 ref DATA_BLOB pOptionEntropy,
32 IntPtr pvReserved,
33 ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
34 int dwFlags,
35 ref DATA_BLOB pDataOut
36 );
37
38 [DllImport("kernel32.dll",CharSet=System.Runtime.InteropServices.CharSet.Auto)]
39 private unsafe static extern int FormatMessage
40 (
41 int dwFlags,
42 ref IntPtr lpSource,
43 int dwMessageId,
44 int dwLanguageId,
45 ref String lpBuffer,
46 int nSize,
47 IntPtr *Arguments
48 );
49 [StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]
50 internal struct DATA_BLOB
51 {
52 public int cbData;
53 public IntPtr pbData;
54 }
55 [StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]
56 internal struct CRYPTPROTECT_PROMPTSTRUCT
57 {
58 public int cbSize;
59 public int dwPromptFlags;
60 public IntPtr hwndApp;
61 public String szPrompt;
62 }
63 static private IntPtr NullPtr=((IntPtr)((int)(0)));
64 private const int CRYPTPROTECT_UI_FORBIDDEN=0x1;
65 private const int CRYPTPROTECT_LOCAL_MACHINE=0x4;
66
67 private Store store;
68 public DataProtector(Store tempStore)
69 {
70 store=tempStore;
71 }
72 public byte[] Encrypt(byte[] plainText,byte[] optionalEntropy)
73 {
74 bool reVal=false;
75 DATA_BLOB plainTextBlob = new DATA_BLOB();
76 DATA_BLOB cipherTextBlob=new DATA_BLOB();
77 DATA_BLOB entropyBlob = new DATA_BLOB();
78 CRYPTPROTECT_PROMPTSTRUCT prompt=new CRYPTPROTECT_PROMPTSTRUCT();
79 InitPromptstruct(ref prompt);
80 int dwFlags;
81 try
82 {
83 try
84 {
85 int byteSize=plainText.Length;
86 plainTextBlob.pbData=Marshal.AllocHGlobal(byteSize);
87 if(IntPtr.Zero==plainTextBlob.pbData)
88 {
89 throw new Exception("Unable to allocate plaintext buffer:");
90 }
91 plainTextBlob.cbData=byteSize;
92 Marshal.Copy(plainText,0,plainTextBlob.pbData,byteSize);
93 }
94 catch(Exception ex)
95 {
96 throw new Exception("Exception marshalling data.:"+ex.Message);
97 }
98 if(Store.USE_NACHINE_STORE==store)
99 {
100 //计算机存储区
101 dwFlags=CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDDEN;
102 if(null==optionalEntropy)
103 {
104 optionalEntropy=new byte[0];
105 }
106 try
107 {
108 int byteSize=optionalEntropy.Length;
109 entropyBlob.pbData=Marshal.AllocHGlobal(optionalEntropy.Length);
110 if(IntPtr.Zero==entropyBlob.pbData)
111 {
112 throw new Exception("Unable to allocate entropy data buffer.");
113 }
114 Marshal.Copy(optionalEntropy,0,entropyBlob.pbData,byteSize);
115 entropyBlob.cbData=byteSize;
116 }
117 catch(Exception ex)
118 {
119 throw new Exception("Exception entropy marshalling data."+ex.Message);
120 }
121 }
122 else
123 {
124 dwFlags=CRYPTPROTECT_UI_FORBIDDEN;
125 }
126 reVal=CryptProtectData(ref plainTextBlob,"",ref entropyBlob,IntPtr.Zero,ref prompt,dwFlags,ref cipherTextBlob);
127 if(false == reVal)
128 {
129 throw new Exception("Encryption failed."+GetErrorMessage(Marshal.GetLastWin32Error()));
130 }
131 }
132 catch(Exception ex)
133 {
134 throw new Exception("Exception encrypting:"+ex.Message);
135 }
136 byte[] cipherText = new byte[cipherTextBlob.cbData];
137 Marshal.Copy(cipherTextBlob.pbData,cipherText,0,cipherTextBlob.cbData);
138 return cipherText;
139 }
140 public byte[] Decrypt(byte[] ciperText,byte[] optionalEntropy)
141 {
142 bool reVal=false;
143 DATA_BLOB plainTextBlob=new DATA_BLOB();
144 DATA_BLOB cipherBlob=new DATA_BLOB();
145 CRYPTPROTECT_PROMPTSTRUCT prompt=new CRYPTPROTECT_PROMPTSTRUCT();
146 InitPromptstruct(ref prompt);
147 try
148 {
149 try
150 {
151 int cipherTextSize=ciperText.Length;
152 cipherBlob.pbData=Marshal.AllocHGlobal(cipherTextSize);
153 if(IntPtr.Zero==cipherBlob.pbData)
154 {
155 throw new Exception("unable to allocate cipherText buffer.");
156 }
157 cipherBlob.cbData=cipherTextSize;
158 Marshal.Copy(ciperText,0,cipherBlob.pbData,cipherBlob.cbData);
159 }
160 catch(Exception ex)
161 {
162 throw new Exception("Exception marshalling data."+ex.Message);
163 }
164 DATA_BLOB entropyBlob=new DATA_BLOB();
165 int dwFlags;
166 if(Store.USE_NACHINE_STORE==store)
167 {
168 dwFlags=CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDDEN;
169 if(null==optionalEntropy)
170 {
171 optionalEntropy=new byte[0];
172 }
173 try
174 {
175 int byteSize=optionalEntropy.Length;
176 entropyBlob.pbData=Marshal.AllocHGlobal(byteSize);
177 if(IntPtr.Zero==entropyBlob.pbData)
178 {
179 throw new Exception("Unable to allocate entropy buffer.");
180 }
181 entropyBlob.cbData=byteSize;
182 Marshal.Copy(optionalEntropy,0,entropyBlob.pbData,byteSize);
183 }
184 catch(Exception ex)
185 {
186 throw new Exception("Exception entropy marshalling data."+ex.Message);
187 }
188 }
189 else
190 {
191 dwFlags=CRYPTPROTECT_UI_FORBIDDEN;
192 }
193 reVal=CryptUnprotectData(ref cipherBlob,null,ref entropyBlob,IntPtr.Zero,ref prompt,dwFlags,ref plainTextBlob);
194 if(false==reVal)
195 {
196 throw new Exception("Decryption failed."+GetErrorMessage(Marshal.GetLastWin32Error()));
197 }
198 if(IntPtr.Zero!=cipherBlob.pbData)
199 {
200 Marshal.FreeHGlobal(cipherBlob.pbData);
201 }
202 if(IntPtr.Zero!=entropyBlob.pbData)
203 {
204 Marshal.FreeHGlobal(entropyBlob.pbData);
205 }
206
207 }
208 catch(Exception ex)
209 {
210 throw new Exception("Exception decrypting."+ex.Message);
211 }
212 byte[] plainText=new byte[plainTextBlob.cbData];
213 Marshal.Copy(plainTextBlob.pbData,plainText,0,plainTextBlob.cbData);
214 return plainText;
215 }
216
217 private void InitPromptstruct(ref CRYPTPROTECT_PROMPTSTRUCT ps)
218 {
219 ps.cbSize=Marshal.SizeOf(typeof(CRYPTPROTECT_PROMPTSTRUCT));
220 ps.dwPromptFlags=0;
221 ps.hwndApp=NullPtr;
222 ps.szPrompt=null;
223 }
224 private unsafe static String GetErrorMessage(int errorCode)
225 {
226 int FORMAT_MESSAGE_ALLOCATE_BUFFER=0x00000100;
227 int FORMAT_MESSAGE_IGNORE_INSERTS=0x00000200;
228 int FORMAT_MESSAGE_FROM_SYSTEM=0x00001000;
229 int messageSize=255;
230 String lpMsgBuf="";
231 int dwFlags=FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS;
232 IntPtr ptrlpSource=new IntPtr();
233 IntPtr ptrArgument=new IntPtr();
234 int retVal=FormatMessage(dwFlags,ref ptrlpSource,errorCode,0,ref lpMsgBuf,messageSize,&ptrArgument);
235 if(0==retVal)
236 {
237 throw new Exception("Failed to format message for error code"+errorCode+".");
238 }
239 return lpMsgBuf;
240 }
241
242 }
243
}
244
using System;2
using System.Text;3
using System.Runtime.InteropServices;4
5
namespace JillZhang.Security6
{
7
public enum Store8
{
9
USE_NACHINE_STORE=1,USE_USER_STORE10
};11
public class DataProtector12
{13
14
[DllImport("Crypt32.dll",SetLastError=true,CharSet=System.Runtime.InteropServices.CharSet.Auto)]15
private static extern bool CryptProtectData16
(17
ref DATA_BLOB pDataIn,18
String szDataDecr,19
ref DATA_BLOB pOptionEntropy,20
IntPtr pvReserved,21
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,22
int dwFlags,23
ref DATA_BLOB pDataOut24
);25
26
[DllImport("Crypt32.dll",SetLastError=true,CharSet=System.Runtime.InteropServices.CharSet.Auto)]27
private static extern bool CryptUnprotectData28
(29
ref DATA_BLOB pDataIn,30
String szDataDecr,31
ref DATA_BLOB pOptionEntropy,32
IntPtr pvReserved,33
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,34
int dwFlags,35
ref DATA_BLOB pDataOut36
);37
38
[DllImport("kernel32.dll",CharSet=System.Runtime.InteropServices.CharSet.Auto)]39
private unsafe static extern int FormatMessage40
(41
int dwFlags,42
ref IntPtr lpSource,43
int dwMessageId,44
int dwLanguageId,45
ref String lpBuffer,46
int nSize,47
IntPtr *Arguments48
);49
[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]50
internal struct DATA_BLOB51
{52
public int cbData;53
public IntPtr pbData;54
}55
[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]56
internal struct CRYPTPROTECT_PROMPTSTRUCT57
{58
public int cbSize;59
public int dwPromptFlags;60
public IntPtr hwndApp;61
public String szPrompt;62
}63
static private IntPtr NullPtr=((IntPtr)((int)(0)));64
private const int CRYPTPROTECT_UI_FORBIDDEN=0x1;65
private const int CRYPTPROTECT_LOCAL_MACHINE=0x4;66
67
private Store store;68
public DataProtector(Store tempStore)69
{70
store=tempStore; 71
}72
public byte[] Encrypt(byte[] plainText,byte[] optionalEntropy)73
{74
bool reVal=false;75
DATA_BLOB plainTextBlob = new DATA_BLOB();76
DATA_BLOB cipherTextBlob=new DATA_BLOB();77
DATA_BLOB entropyBlob = new DATA_BLOB();78
CRYPTPROTECT_PROMPTSTRUCT prompt=new CRYPTPROTECT_PROMPTSTRUCT();79
InitPromptstruct(ref prompt);80
int dwFlags;81
try82
{83
try84
{85
int byteSize=plainText.Length;86
plainTextBlob.pbData=Marshal.AllocHGlobal(byteSize);87
if(IntPtr.Zero==plainTextBlob.pbData)88
{89
throw new Exception("Unable to allocate plaintext buffer:");90
}91
plainTextBlob.cbData=byteSize;92
Marshal.Copy(plainText,0,plainTextBlob.pbData,byteSize); 93
}94
catch(Exception ex)95
{96
throw new Exception("Exception marshalling data.:"+ex.Message);97
}98
if(Store.USE_NACHINE_STORE==store)99
{100
//计算机存储区101
dwFlags=CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDDEN;102
if(null==optionalEntropy)103
{104
optionalEntropy=new byte[0];105
}106
try107
{108
int byteSize=optionalEntropy.Length;109
entropyBlob.pbData=Marshal.AllocHGlobal(optionalEntropy.Length);110
if(IntPtr.Zero==entropyBlob.pbData)111
{112
throw new Exception("Unable to allocate entropy data buffer.");113
}114
Marshal.Copy(optionalEntropy,0,entropyBlob.pbData,byteSize);115
entropyBlob.cbData=byteSize;116
}117
catch(Exception ex)118
{119
throw new Exception("Exception entropy marshalling data."+ex.Message);120
} 121
}122
else123
{124
dwFlags=CRYPTPROTECT_UI_FORBIDDEN;125
}126
reVal=CryptProtectData(ref plainTextBlob,"",ref entropyBlob,IntPtr.Zero,ref prompt,dwFlags,ref cipherTextBlob);127
if(false == reVal)128
{129
throw new Exception("Encryption failed."+GetErrorMessage(Marshal.GetLastWin32Error()));130
}131
}132
catch(Exception ex)133
{134
throw new Exception("Exception encrypting:"+ex.Message);135
}136
byte[] cipherText = new byte[cipherTextBlob.cbData];137
Marshal.Copy(cipherTextBlob.pbData,cipherText,0,cipherTextBlob.cbData);138
return cipherText;139
}140
public byte[] Decrypt(byte[] ciperText,byte[] optionalEntropy)141
{142
bool reVal=false;143
DATA_BLOB plainTextBlob=new DATA_BLOB();144
DATA_BLOB cipherBlob=new DATA_BLOB();145
CRYPTPROTECT_PROMPTSTRUCT prompt=new CRYPTPROTECT_PROMPTSTRUCT();146
InitPromptstruct(ref prompt);147
try148
{149
try150
{151
int cipherTextSize=ciperText.Length;152
cipherBlob.pbData=Marshal.AllocHGlobal(cipherTextSize);153
if(IntPtr.Zero==cipherBlob.pbData)154
{155
throw new Exception("unable to allocate cipherText buffer.");156
}157
cipherBlob.cbData=cipherTextSize;158
Marshal.Copy(ciperText,0,cipherBlob.pbData,cipherBlob.cbData);159
}160
catch(Exception ex)161
{162
throw new Exception("Exception marshalling data."+ex.Message);163
}164
DATA_BLOB entropyBlob=new DATA_BLOB();165
int dwFlags;166
if(Store.USE_NACHINE_STORE==store)167
{168
dwFlags=CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDDEN;169
if(null==optionalEntropy)170
{171
optionalEntropy=new byte[0];172
}173
try174
{175
int byteSize=optionalEntropy.Length;176
entropyBlob.pbData=Marshal.AllocHGlobal(byteSize);177
if(IntPtr.Zero==entropyBlob.pbData)178
{179
throw new Exception("Unable to allocate entropy buffer.");180
}181
entropyBlob.cbData=byteSize;182
Marshal.Copy(optionalEntropy,0,entropyBlob.pbData,byteSize);183
}184
catch(Exception ex)185
{186
throw new Exception("Exception entropy marshalling data."+ex.Message);187
}188
}189
else190
{191
dwFlags=CRYPTPROTECT_UI_FORBIDDEN;192
}193
reVal=CryptUnprotectData(ref cipherBlob,null,ref entropyBlob,IntPtr.Zero,ref prompt,dwFlags,ref plainTextBlob);194
if(false==reVal)195
{196
throw new Exception("Decryption failed."+GetErrorMessage(Marshal.GetLastWin32Error()));197
}198
if(IntPtr.Zero!=cipherBlob.pbData)199
{200
Marshal.FreeHGlobal(cipherBlob.pbData);201
}202
if(IntPtr.Zero!=entropyBlob.pbData)203
{204
Marshal.FreeHGlobal(entropyBlob.pbData);205
}206
207
}208
catch(Exception ex)209
{210
throw new Exception("Exception decrypting."+ex.Message);211
}212
byte[] plainText=new byte[plainTextBlob.cbData];213
Marshal.Copy(plainTextBlob.pbData,plainText,0,plainTextBlob.cbData);214
return plainText;215
}216
217
private void InitPromptstruct(ref CRYPTPROTECT_PROMPTSTRUCT ps)218
{219
ps.cbSize=Marshal.SizeOf(typeof(CRYPTPROTECT_PROMPTSTRUCT));220
ps.dwPromptFlags=0;221
ps.hwndApp=NullPtr;222
ps.szPrompt=null;223
}224
private unsafe static String GetErrorMessage(int errorCode)225
{226
int FORMAT_MESSAGE_ALLOCATE_BUFFER=0x00000100;227
int FORMAT_MESSAGE_IGNORE_INSERTS=0x00000200;228
int FORMAT_MESSAGE_FROM_SYSTEM=0x00001000;229
int messageSize=255;230
String lpMsgBuf="";231
int dwFlags=FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS;232
IntPtr ptrlpSource=new IntPtr();233
IntPtr ptrArgument=new IntPtr();234
int retVal=FormatMessage(dwFlags,ref ptrlpSource,errorCode,0,ref lpMsgBuf,messageSize,&ptrArgument);235
if(0==retVal)236
{237
throw new Exception("Failed to format message for error code"+errorCode+".");238
}239
return lpMsgBuf;240
}241
242
}243
}244
作者：jillzhang
出处：http://jillzhang.cnblogs.com/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
出处：http://jillzhang.cnblogs.com/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
