Java加密解密快速入门下篇【包括MD5、BASE64、DES、RSA等算法】_JAVA_编程开发_程序员俱乐部

在上一篇博客中已经简要的介绍了MD5、BASE64、DES、RSA等算法在Java中的具体应用。现在可以考虑对这些代码封装成一个工具类EncryptUtil，然后再补充一下Commons Codec对BASE64的扩展支持！

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<一>. EncryptUtil工具类：

?1. 使用commons-logging记录异常日志。

?2. 提取常量字段、公共字段。

?3. 提取公共方法：?

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1. //创建密钥??
2. createSecretKey(String?key):Key???
3. //加密解密??
4. processCipher(byte[]?processData,?Key?key,?int?opsMode,?String?algorithm):byte[]??

? 4.?EncryptUtil类的完整代码：?

1. /*?
2. ?*?Copyright?(c)?2014,?Nick?Xu,?All?rights?reserved.?
3. ?*/??
4. package?com.excelsoft.common.crypto;??
5. ??
6. import?java.io.IOException;??
7. import?java.security.Key;??
8. import?java.security.KeyPair;??
9. import?java.security.KeyPairGenerator;??
10. import?java.security.MessageDigest;??
11. import?java.security.NoSuchAlgorithmException;??
12. import?java.security.PrivateKey;??
13. import?java.security.PublicKey;??
14. import?java.security.SecureRandom;??
15. import?java.security.Signature;??
16. ??
17. import?javax.crypto.Cipher;??
18. import?javax.crypto.SecretKey;??
19. import?javax.crypto.SecretKeyFactory;??
20. import?javax.crypto.spec.DESKeySpec;??
21. ??
22. import?org.apache.commons.logging.Log;??
23. import?org.apache.commons.logging.LogFactory;??
24. ??
25. import?sun.misc.BASE64Decoder;??
26. import?sun.misc.BASE64Encoder;??
27. ??
28. /**?
29. ?*?功能简述:?加密解密工具类，对MD5/BASE64/DES/RSA等算法提供了包装.?
30. ?*?@author?Nick?Xu?
31. ?*?@version?1.0?
32. ?*/??
33. public?class?EncryptUtil?{??
34. ????private?static?Log?logger?=?LogFactory.getLog(EncryptUtil.class);??
35. ??????
36. ????private?static?final?int?KEY_SIZE?=?1024;??
37. ????private?static?final?String??MD5_ALGORITHM=?"md5";??
38. ????private?static?final?String??DES_ALGORITHM=?"des";??
39. ????private?static?final?String??RSA_ALGORITHM=?"rsa";??
40. ????private?static?final?String??SIGNATURE_ALGORITHM=?"MD5withRSA";??
41. ??????
42. ????private?static?MessageDigest?md5;??
43. ????private?static?BASE64Encoder?encoder;??
44. ????private?static?BASE64Decoder?decoder;??
45. ????private?static?SecureRandom?random;??
46. ????private?static?KeyPair?keyPair;??
47. ??????
48. ????private?EncryptUtil()?{??
49. ????}??
50. ??????
51. ????static?{??
52. ????????try?{??
53. ????????????md5?=?MessageDigest.getInstance(MD5_ALGORITHM);??
54. ??????????????
55. ????????????KeyPairGenerator?keyPairGenerator?=?KeyPairGenerator.getInstance(RSA_ALGORITHM);??
56. ????????????keyPairGenerator.initialize(KEY_SIZE);??
57. ????????????keyPair?=?keyPairGenerator.generateKeyPair();??
58. ????????}??
59. ????????catch?(NoSuchAlgorithmException?e)?{??
60. ????????????//?Exception?handler??
61. ????????????logger.error(e);??
62. ????????}??
63. ????????encoder?=?new?BASE64Encoder();??
64. ????????decoder?=?new?BASE64Decoder();??
65. ????????random?=?new?SecureRandom();??
66. ????}??
67. ??????
68. ????/**?
69. ?????*?功能简述:?使用md5进行单向加密.?
70. ?????*/??
71. ????public?static?String?encryptMD5(String?plainText)?{??
72. ????????byte[]?cipherData?=?md5.digest(plainText.getBytes());??
73. ????????StringBuilder?builder?=?new?StringBuilder();??
74. ????????for(byte?cipher?:?cipherData)?{??
75. ????????????String?toHexStr?=?Integer.toHexString(cipher?&?0xff);??
76. ????????????builder.append(toHexStr.length()?==?1???"0"?+?toHexStr?:?toHexStr);??
77. ????????}??
78. ????????return?builder.toString();??
79. ????}??
80. ??????
81. ????/**?
82. ?????*?功能简述:?使用BASE64进行加密.?
83. ?????*?@param?plainData?明文数据?
84. ?????*?@return?加密之后的文本内容?
85. ?????*/??
86. ????public?static?String?encryptBASE64(byte[]?plainData)?{??
87. ????????return?encoder.encode(plainData);??
88. ????}??
89. ??????
90. ????/**?
91. ?????*?功能简述:?使用BASE64进行解密.?
92. ?????*?@param?cipherText?密文文本?
93. ?????*?@return?解密之后的数据?
94. ?????*/??
95. ????public?static?byte[]?decryptBASE64(String?cipherText)?{??
96. ????????byte[]?plainData?=?null;??
97. ????????try?{??
98. ????????????plainData?=??decoder.decodeBuffer(cipherText);??
99. ????????}??
100. ????????catch?(IOException?e)?{??
101. ????????????//?Exception?handler??
102. ????????????logger.error(e);??
103. ????????}??
104. ????????return?plainData;??
105. ????}??
106. ??????
107. ????/**?
108. ?????*?功能简述:?使用DES算法进行加密.?
109. ?????*?@param?plainData?明文数据?
110. ?????*?@param?key???加密密钥?
111. ?????*?@return???
112. ?????*/??
113. ????public?static?byte[]?encryptDES(byte[]?plainData,?String?key)?{??
114. ????????return?processCipher(plainData,?createSecretKey(key),?Cipher.ENCRYPT_MODE,?DES_ALGORITHM);??
115. ????}??
116. ??????
117. ????/**?
118. ?????*?功能简述:?使用DES算法进行解密.?
119. ?????*?@param?cipherData????密文数据?
120. ?????*?@param?key???解密密钥?
121. ?????*?@return?
122. ?????*/??
123. ????public?static?byte[]?decryptDES(byte[]?cipherData,?String?key)?{??
124. ????????return?processCipher(cipherData,?createSecretKey(key),?Cipher.DECRYPT_MODE,?DES_ALGORITHM);??
125. ????}??
126. ??????
127. ????/**?
128. ?????*?功能简述:?根据key创建密钥SecretKey.?
129. ?????*?@param?key??
130. ?????*?@return?
131. ?????*/??
132. ????private?static?SecretKey?createSecretKey(String?key)?{??
133. ????????SecretKey?secretKey?=?null;??
134. ????????try?{??
135. ????????????DESKeySpec?keySpec?=?new?DESKeySpec(key.getBytes());??
136. ????????????SecretKeyFactory?keyFactory?=?SecretKeyFactory.getInstance(DES_ALGORITHM);??
137. ????????????secretKey?=?keyFactory.generateSecret(keySpec);??
138. ????????}??
139. ????????catch?(Exception?e)?{??
140. ????????????//?Exception?handler??
141. ????????????logger.error(e);??
142. ????????}??
143. ????????return?secretKey;??
144. ????}??
145. ??????
146. ????/**?
147. ?????*?功能简述:?加密/解密处理流程.?
148. ?????*?@param?processData???待处理的数据?
149. ?????*?@param?key???提供的密钥?
150. ?????*?@param?opsMode???工作模式?
151. ?????*?@param?algorithm???使用的算法?
152. ?????*?@return???
153. ?????*/??
154. ????private?static?byte[]?processCipher(byte[]?processData,?Key?key,?int?opsMode,?String?algorithm)?{??
155. ????????try{???
156. ????????????Cipher?cipher?=?Cipher.getInstance(algorithm);??
157. ????????????cipher.init(opsMode,?key,?random);??
158. ????????????return?cipher.doFinal(processData);??
159. ????????}??
160. ????????catch?(Exception?e)?{??
161. ????????????//?Exception?handler??
162. ????????????logger.error(e);??
163. ????????}??
164. ????????return?null;??
165. ????}??
166. ??????
167. ????/**?
168. ?????*?功能简述:?创建私钥，用于RSA非对称加密.?
169. ?????*?@return?
170. ?????*/??
171. ????public?static?PrivateKey?createPrivateKey()?{??
172. ????????return?keyPair.getPrivate();??
173. ????}??
174. ??????
175. ????/**?
176. ?????*?功能简述:?创建公钥，用于RSA非对称加密.?
177. ?????*?@return?
178. ?????*/??
179. ????public?static?PublicKey?createPublicKey()?{??
180. ????????return?keyPair.getPublic();??
181. ????}??
182. ??????
183. ????/**?
184. ?????*?功能简述:?使用RSA算法加密.?
185. ?????*?@param?plainData?明文数据?
186. ?????*?@param?key???密钥?
187. ?????*?@return?
188. ?????*/??
189. ????public?static?byte[]?encryptRSA(byte[]?plainData,?Key?key)?{??
190. ????????return?processCipher(plainData,?key,?Cipher.ENCRYPT_MODE,?RSA_ALGORITHM);??
191. ????}??
192. ??????
193. ????/**?
194. ?????*?功能简述:?使用RSA算法解密.?
195. ?????*?@param?cipherData????密文数据?
196. ?????*?@param?key???密钥?
197. ?????*?@return?
198. ?????*/??
199. ????public?static?byte[]?decryptRSA(byte[]?cipherData,?Key?key)?{??
200. ????????return?processCipher(cipherData,?key,?Cipher.DECRYPT_MODE,?RSA_ALGORITHM);??
201. ????}??
202. ??????
203. ????/**?
204. ?????*?功能简述:?使用私钥对加密数据创建数字签名.?
205. ?????*?@param?cipherData?????已经加密过的数据?
206. ?????*?@param?privateKey????私钥?
207. ?????*?@return?
208. ?????*/??
209. ????public?static?byte[]?createSignature(byte[]?cipherData,?PrivateKey?privateKey)?{??
210. ????????try?{??
211. ????????????Signature?signature??=?Signature.getInstance(SIGNATURE_ALGORITHM);??
212. ????????????signature.initSign(privateKey);??
213. ????????????signature.update(cipherData);??
214. ????????????return?signature.sign();??
215. ????????}??
216. ????????catch?(Exception?e)?{??
217. ????????????//?Exception?handler??
218. ????????????logger.error(e);???
219. ????????}??
220. ????????return?null;??
221. ????}??
222. ??????
223. ????/**?
224. ?????*?功能简述:?使用公钥对数字签名进行验证.?
225. ?????*?@param?signData??数字签名?
226. ?????*?@param?publicKey?公钥?
227. ?????*?@return?
228. ?????*/??
229. ????public?static?boolean?verifySignature(byte[]?cipherData,?byte[]?signData,?PublicKey?publicKey)?{??
230. ????????try?{??
231. ????????????Signature?signature??=?Signature.getInstance(SIGNATURE_ALGORITHM);??
232. ????????????signature.initVerify(publicKey);??
233. ????????????signature.update(cipherData);??
234. ????????????return?signature.verify(signData);??
235. ????????}??
236. ????????catch?(Exception?e)?{??
237. ????????????//?Exception?handler??
238. ????????????logger.error(e);??
239. ????????}??
240. ????????return?false;??
241. ????}??
242. }??

?

<二>. Commons Codec对BASE64的扩展支持：

? ? ? JDK提供了对BASE64的标准支持，每隔76个字符进行换行\r\n，并且包含+、=、/等特殊字符不适合作为url参数传递。因此通常都会使用Commons Codec来进行BASE64的加密和解密。下载commons-codec-1.8.jar并添加到lib下面，注意选择高版本，低版本有些方法不支持。

?1.?是否换行：

1. byte[]?cipherData?=?Base64.encodeBase64(plainText.getBytes());?//默认不换行????
2. byte[]?cipherData?=?Base64.encodeBase64(plainText.getBytes(),?false);?//取消换行??
3. byte[]?cipherData?=?Base64.encodeBase64Chunked(plainText.getBytes());?//进行换行??
4. String?cipherText?=?Base64.encodeBase64String(plainText.getBytes());?//转为字符串??

? 2.?安全的url：转换+为-、/为_、将多余的=去掉

1. byte[]?cipherData?=?Base64.encodeBase64(plainText.getBytes(),?false,?true);??
2. byte[]?cipherData?=?Base64.encodeBase64URLSafe(plainText.getBytes());??
3. String?cipherText?=?Base64.encodeBase64URLSafeString(plainText.getBytes());??

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