兼容javascript和C#的RSA加密解密算法，对web提交的数据进行加密传输
Web应用中往往涉及到敏感的数据，由于HTTP协议以明文的形式与服务器进行交互，因此可以通过截获请求的数据包进行分析来盗取有用的信息。虽然https可以对传输的数据进行加密，但是必须要申请证书（一般都是收费的），成本较高。那么问题来了，如果对web提交的敏感数据进行加密呢？web应用中，前端的数据处理和交互基本上都是靠javascript来完成，后台的逻辑处理可以C#(java)等进行处理。
微软的C#中虽然有RSA算法，但是格式和OpenSSL生成的公钥/私钥文件格式并不兼容。这个也给贯通前后台的RSA加密解密带来了难度。为了兼容OpenSSL生成的公钥/私钥文件格式，贯通javascript和C#的RSA加密解密算法，必须对C#内置的方法进行再度封装。
下面以登录为例，用户在密码框输入密码后，javascript发送ajax请求时，对密码先进行rsa加密后再发送，服务器接收到加密后的密码后，先对其进行解密， 然后再验证登录是否成功。
1 为了进行RSA加密解密，首先需要用openssl生成一对公钥和私钥（没有的先下载openssl)：
1） 打开openssl.exe文件，输入 genrsa -out openssl_rsa_priv.pem 1024
此命令在openssl.exe同目录下生成openssl_rsa_private_key.pem文件。
2） 生成公钥 rsa -in openssl_rsa__private.pem -pubout -out openssl_rsa__public.pem
以上命令会创建如下的文件：
这个文件可以用文本编辑器进行打开，查看内容。
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC0w036ClSD0LvxPROMun0u022R
OJlZE6P3m+gjq3gpi4n7lo8jhTqMqgccDbVJqnIfMzWS9O3lnlQXWTxJ3B4XJ52F
AcriY5brOXUVgBLx5QMHLLd1gtJnmG4i7r4ytgX7XVKRnojR6zca1YnS0lbGGDF1
CGllB1riNrdksSQP+wIDAQAB
-----END PUBLIC KEY-----
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
2 用jsencrypt对密码进行加密：
首先需要导入js包文件
<script src="dist/js/jsencrypt.js"></script>
1 var encrypt = new JSEncrypt();
2 var pubkey = "-----BEGIN PUBLIC KEY----- \
3 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDAj0dPnBMf3Z4VT1B8Ee6bjKNs \
4 hlYj7xvGijAa8RCdmGR7mrtrExnk8mdUlwdcS05gc4SSFOyWJcYtKUHpWn8/pkS0 \
5 vgGOl9Bzn0Xt9hiqTb3pZAfykNrMDGZMgJgfD6KTnfzVUAOupvxjcGkcoj6/vV5I \
6 eMcx8mT/z3elfsDSjQIDAQAB \
7 -----END PUBLIC KEY-----";
8 encrypt.setPublicKey(pubkey);
9 var encrypted = encrypt.encrypt($('#txtpwd').val());
10 //console.log(encrypted);
11 $.ajax({
12 type: "POST",
13 url: "http://localhost:24830/services/rsa_pem.ashx",
14 data: { "pwd": encrypted },
15 dataType: "Json",
16 error: function (xhr, status, error) {
17 // alert(error);
18 $("#txtInfo").text(' 请求服务器失败！');
19 $(that).text('登 录');
20 $(that).attr('disabled', false);
21 },
22 success: function (json) {
23
24 if (uid == "admin" && json.data=="000") {
25 window.location.href = "index.html";
26 }
27 else {
28 $("#txtInfo").text(' 用户名或者密码错误！');
29 $(that).text('登 录');
30 $(that).attr('disabled', false);
31 }
32 }
33 });
3 后台用C#进行解密
1 using System;
2 using System.Collections.Generic;
3 using System.IO;
4 using System.Linq;
5 using System.Security.Cryptography;
6 using System.Text;
7 using System.Threading.Tasks;
8
9 namespace CMCloud.SaaS
10 {
11 public class RSACryptoService
12 {
13 private RSACryptoServiceProvider _privateKeyRsaProvider;
14 private RSACryptoServiceProvider _publicKeyRsaProvider;
15
16 /// <summary>
17 /// RSA解密
18 /// </summary>
19 /// <param name="cipherText"></param>
20 /// <returns></returns>
21 public string Decrypt(string cipherText)
22 {
23 if (_privateKeyRsaProvider == null)
24 {
25 throw new Exception("_privateKeyRsaProvider is null");
26 }
27 return Decrypt2(cipherText);
28 }
29 /// <summary>
30 /// RSA加密
31 /// </summary>
32 /// <param name="text"></param>
33 /// <returns></returns>
34 public string Encrypt(string text)
35 {
36 if (_publicKeyRsaProvider == null)
37 {
38 throw new Exception("_publicKeyRsaProvider is null");
39 }
40 return Encrypt2(text);
41 //return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(Encoding.UTF8.GetBytes(text), false));
42
43 }
44 private string Encrypt2(string text)
45 {
46
47
48 Byte[] PlaintextData = Encoding.UTF8.GetBytes(text);
49 int MaxBlockSize = _publicKeyRsaProvider.KeySize / 8 - 11;//加密块最大长度限制
50
51 if (PlaintextData.Length <= MaxBlockSize)
52 {
53 return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(PlaintextData, false));
54 }
55 else
56 {
57 using (MemoryStream PlaiStream = new MemoryStream(PlaintextData))
58 using (MemoryStream CrypStream = new MemoryStream())
59 {
60 Byte[] Buffer = new Byte[MaxBlockSize];
61 int BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
62
63 while (BlockSize > 0)
64 {
65 Byte[] ToEncrypt = new Byte[BlockSize];
66 Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize);
67
68 Byte[] Cryptograph = _publicKeyRsaProvider.Encrypt(ToEncrypt, false);
69 CrypStream.Write(Cryptograph, 0, Cryptograph.Length);
70
71 BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
72 }
73
74 return Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None);
75 }
76 }
77
78
79
80
81 }
82
83 private string Decrypt2(string ciphertext)
84 {
85
86
87 Byte[] CiphertextData = Convert.FromBase64String(ciphertext);
88 int MaxBlockSize = _privateKeyRsaProvider.KeySize / 8; //解密块最大长度限制
89
90 if (CiphertextData.Length <= MaxBlockSize)
91 return System.Text.Encoding.UTF8.GetString(_privateKeyRsaProvider.Decrypt(CiphertextData, false));
92
93 using (MemoryStream CrypStream = new MemoryStream(CiphertextData))
94 using (MemoryStream PlaiStream = new MemoryStream())
95 {
96 Byte[] Buffer = new Byte[MaxBlockSize];
97 int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
98
99 while (BlockSize > 0)
100 {
101 Byte[] ToDecrypt = new Byte[BlockSize];
102 Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize);
103
104 Byte[] Plaintext = _privateKeyRsaProvider.Decrypt(ToDecrypt, false);
105 PlaiStream.Write(Plaintext, 0, Plaintext.Length);
106
107 BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
108 }
109
110 return System.Text.Encoding.UTF8.GetString(PlaiStream.ToArray());
111 }
112 }
113 public RSACryptoService(string privateKey, string publicKey = null)
114 {
115 if (!string.IsNullOrEmpty(privateKey))
116 {
117 _privateKeyRsaProvider = CreateRsaProviderFromPrivateKey(privateKey);
118 }
119
120 if (!string.IsNullOrEmpty(publicKey))
121 {
122 _publicKeyRsaProvider = CreateRsaProviderFromPublicKey(publicKey);
123 }
124 }
125
126
127
128 private RSACryptoServiceProvider CreateRsaProviderFromPrivateKey(string privateKey)
129 {
130 var privateKeyBits = System.Convert.FromBase64String(privateKey);
131
132 var RSA = new RSACryptoServiceProvider();
133 var RSAparams = new RSAParameters();
134
135 using (BinaryReader binr = new BinaryReader(new MemoryStream(privateKeyBits)))
136 {
137 byte bt = 0;
138 ushort twobytes = 0;
139 twobytes = binr.ReadUInt16();
140 if (twobytes == 0x8130)
141 binr.ReadByte();
142 else if (twobytes == 0x8230)
143 binr.ReadInt16();
144 else
145 throw new Exception("Unexpected value read binr.ReadUInt16()");
146
147 twobytes = binr.ReadUInt16();
148 if (twobytes != 0x0102)
149 throw new Exception("Unexpected version");
150
151 bt = binr.ReadByte();
152 if (bt != 0x00)
153 throw new Exception("Unexpected value read binr.ReadByte()");
154
155 RSAparams.Modulus = binr.ReadBytes(GetIntegerSize(binr));
156 RSAparams.Exponent = binr.ReadBytes(GetIntegerSize(binr));
157 RSAparams.D = binr.ReadBytes(GetIntegerSize(binr));
158 RSAparams.P = binr.ReadBytes(GetIntegerSize(binr));
159 RSAparams.Q = binr.ReadBytes(GetIntegerSize(binr));
160 RSAparams.DP = binr.ReadBytes(GetIntegerSize(binr));
161 RSAparams.DQ = binr.ReadBytes(GetIntegerSize(binr));
162 RSAparams.InverseQ = binr.ReadBytes(GetIntegerSize(binr));
163 }
164
165 RSA.ImportParameters(RSAparams);
166 return RSA;
167 }
168
169 private int GetIntegerSize(BinaryReader binr)
170 {
171 byte bt = 0;
172 byte lowbyte = 0x00;
173 byte highbyte = 0x00;
174 int count = 0;
175 bt = binr.ReadByte();
176 if (bt != 0x02)
177 return 0;
178 bt = binr.ReadByte();
179
180 if (bt == 0x81)
181 count = binr.ReadByte();
182 else
183 if (bt == 0x82)
184 {
185 highbyte = binr.ReadByte();
186 lowbyte = binr.ReadByte();
187 byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
188 count = BitConverter.ToInt32(modint, 0);
189 }
190 else
191 {
192 count = bt;
193 }
194
195 while (binr.ReadByte() == 0x00)
196 {
197 count -= 1;
198 }
199 binr.BaseStream.Seek(-1, SeekOrigin.Current);
200 return count;
201 }
202
203 private RSACryptoServiceProvider CreateRsaProviderFromPublicKey(string publicKeyString)
204 {
205 // encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
206 byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
207 byte[] x509key;
208 byte[] seq = new byte[15];
209 int x509size;
210
211 x509key = Convert.FromBase64String(publicKeyString);
212 x509size = x509key.Length;
213
214 // --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
215 using (MemoryStream mem = new MemoryStream(x509key))
216 {
217 using (BinaryReader binr = new BinaryReader(mem)) //wrap Memory Stream with BinaryReader for easy reading
218 {
219 byte bt = 0;
220 ushort twobytes = 0;
221
222 twobytes = binr.ReadUInt16();
223 if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
224 binr.ReadByte(); //advance 1 byte
225 else if (twobytes == 0x8230)
226 binr.ReadInt16(); //advance 2 bytes
227 else
228 return null;
229
230 seq = binr.ReadBytes(15); //read the Sequence OID
231 if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct
232 return null;
233
234 twobytes = binr.ReadUInt16();
235 if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
236 binr.ReadByte(); //advance 1 byte
237 else if (twobytes == 0x8203)
238 binr.ReadInt16(); //advance 2 bytes
239 else
240 return null;
241
242 bt = binr.ReadByte();
243 if (bt != 0x00) //expect null byte next
244 return null;
245
246 twobytes = binr.ReadUInt16();
247 if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
248 binr.ReadByte(); //advance 1 byte
249 else if (twobytes == 0x8230)
250 binr.ReadInt16(); //advance 2 bytes
251 else
252 return null;
253
254 twobytes = binr.ReadUInt16();
255 byte lowbyte = 0x00;
256 byte highbyte = 0x00;
257
258 if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
259 lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus
260 else if (twobytes == 0x8202)
261 {
262 highbyte = binr.ReadByte(); //advance 2 bytes
263 lowbyte = binr.ReadByte();
264 }
265 else
266 return null;
267 byte[] modint = { lowbyte, highbyte, 0x00, 0x00 }; //reverse byte order since asn.1 key uses big endian order
268 int modsize = BitConverter.ToInt32(modint, 0);
269
270 int firstbyte = binr.PeekChar();
271 if (firstbyte == 0x00)
272 { //if first byte (highest order) of modulus is zero, don't include it
273 binr.ReadByte(); //skip this null byte
274 modsize -= 1; //reduce modulus buffer size by 1
275 }
276
277 byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes
278
279 if (binr.ReadByte() != 0x02) //expect an Integer for the exponent data
280 return null;
281 int expbytes = (int)binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values)
282 byte[] exponent = binr.ReadBytes(expbytes);
283
284 // ------- create RSACryptoServiceProvider instance and initialize with public key -----
285 RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
286 RSAParameters RSAKeyInfo = new RSAParameters();
287 RSAKeyInfo.Modulus = modulus;
288 RSAKeyInfo.Exponent = exponent;
289 RSA.ImportParameters(RSAKeyInfo);
290
291 return RSA;
292 }
293
294 }
295 }
296
297 private bool CompareBytearrays(byte[] a, byte[] b)
298 {
299 if (a.Length != b.Length)
300 return false;
301 int i = 0;
302 foreach (byte c in a)
303 {
304 if (c != b[i])
305 return false;
306 i++;
307 }
308 return true;
309 }
310 }
311 }
虽然将公钥暴露在js文件中，但是如果需要解密得到明文，必须需要私钥（这个存储在后台，不容易获取）。
调试运行，可以看到获取的密码是加密后的数据，然后在后台可以进行解密获取到明文。
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出处：http://www.cnblogs.com/isaboy/
声明：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://www.cnblogs.com/isaboy/
声明：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。
