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Java加密技术（5）

2012-12-20 
Java加密技术（五）?? 接下来我们分析DH加密算法，一种适基于密钥一致协议的加密算法。?通过java代码实现如下：

Java加密技术（五）

?? 接下来我们分析DH加密算法，一种适基于密钥一致协议的加密算法。?

  • Java加密技术（5）
  • Java加密技术（5）
    通过java代码实现如下：Coder类见Java代码
    1. import?java.security.Key;??
    2. import?java.security.KeyFactory;??
    3. import?java.security.KeyPair;??
    4. import?java.security.KeyPairGenerator;??
    5. import?java.security.PublicKey;??
    6. import?java.security.spec.PKCS8EncodedKeySpec;??
    7. import?java.security.spec.X509EncodedKeySpec;??
    8. import?java.util.HashMap;??
    9. import?java.util.Map;??
    10. ??
    11. import?javax.crypto.Cipher;??
    12. import?javax.crypto.KeyAgreement;??
    13. import?javax.crypto.SecretKey;??
    14. import?javax.crypto.interfaces.DHPrivateKey;??
    15. import?javax.crypto.interfaces.DHPublicKey;??
    16. import?javax.crypto.spec.DHParameterSpec;??
    17. ??
    18. /**?
    19. ?*?DH安全编码组件?
    20. ?*??
    21. ?*?@author?梁栋?
    22. ?*?@version?1.0?
    23. ?*?@since?1.0?
    24. ?*/??
    25. public?abstract?class?DHCoder?extends?Coder?{??
    26. ????public?static?final?String?ALGORITHM?=?"DH";??
    27. ??
    28. ????/**?
    29. ?????*?默认密钥字节数?
    30. ?????*??
    31. ?????*?<pre>?
    32. ?????*?DH?
    33. ?????*?Default?Keysize?1024???
    34. ?????*?Keysize?must?be?a?multiple?of?64,?ranging?from?512?to?1024?(inclusive).?
    35. ?????*?</pre>?
    36. ?????*/??
    37. ????private?static?final?int?KEY_SIZE?=?1024;??
    38. ??
    39. ????/**?
    40. ?????*?DH加密下需要一种对称加密算法对数据加密，这里我们使用DES，也可以使用其他对称加密算法。?
    41. ?????*/??
    42. ????public?static?final?String?SECRET_ALGORITHM?=?"DES";??
    43. ????private?static?final?String?PUBLIC_KEY?=?"DHPublicKey";??
    44. ????private?static?final?String?PRIVATE_KEY?=?"DHPrivateKey";??
    45. ??
    46. ????/**?
    47. ?????*?初始化甲方密钥?
    48. ?????*??
    49. ?????*?@return?
    50. ?????*?@throws?Exception?
    51. ?????*/??
    52. ????public?static?Map<String,?Object>?initKey()?throws?Exception?{??
    53. ????????KeyPairGenerator?keyPairGenerator?=?KeyPairGenerator??
    54. ????????????????.getInstance(ALGORITHM);??
    55. ????????keyPairGenerator.initialize(KEY_SIZE);??
    56. ??
    57. ????????KeyPair?keyPair?=?keyPairGenerator.generateKeyPair();??
    58. ??
    59. ????????//?甲方公钥??
    60. ????????DHPublicKey?publicKey?=?(DHPublicKey)?keyPair.getPublic();??
    61. ??
    62. ????????//?甲方私钥??
    63. ????????DHPrivateKey?privateKey?=?(DHPrivateKey)?keyPair.getPrivate();??
    64. ??
    65. ????????Map<String,?Object>?keyMap?=?new?HashMap<String,?Object>(2);??
    66. ??
    67. ????????keyMap.put(PUBLIC_KEY,?publicKey);??
    68. ????????keyMap.put(PRIVATE_KEY,?privateKey);??
    69. ????????return?keyMap;??
    70. ????}??
    71. ??
    72. ????/**?
    73. ?????*?初始化乙方密钥?
    74. ?????*??
    75. ?????*?@param?key?
    76. ?????*????????????甲方公钥?
    77. ?????*?@return?
    78. ?????*?@throws?Exception?
    79. ?????*/??
    80. ????public?static?Map<String,?Object>?initKey(String?key)?throws?Exception?{??
    81. ????????//?解析甲方公钥??
    82. ????????byte[]?keyBytes?=?decryptBASE64(key);??
    83. ????????X509EncodedKeySpec?x509KeySpec?=?new?X509EncodedKeySpec(keyBytes);??
    84. ????????KeyFactory?keyFactory?=?KeyFactory.getInstance(ALGORITHM);??
    85. ????????PublicKey?pubKey?=?keyFactory.generatePublic(x509KeySpec);??
    86. ??
    87. ????????//?由甲方公钥构建乙方密钥??
    88. ????????DHParameterSpec?dhParamSpec?=?((DHPublicKey)?pubKey).getParams();??
    89. ??
    90. ????????KeyPairGenerator?keyPairGenerator?=?KeyPairGenerator??
    91. ????????????????.getInstance(keyFactory.getAlgorithm());??
    92. ????????keyPairGenerator.initialize(dhParamSpec);??
    93. ??
    94. ????????KeyPair?keyPair?=?keyPairGenerator.generateKeyPair();??
    95. ??
    96. ????????//?乙方公钥??
    97. ????????DHPublicKey?publicKey?=?(DHPublicKey)?keyPair.getPublic();??
    98. ??
    99. ????????//?乙方私钥??
    100. ????????DHPrivateKey?privateKey?=?(DHPrivateKey)?keyPair.getPrivate();??
    101. ??
    102. ????????Map<String,?Object>?keyMap?=?new?HashMap<String,?Object>(2);??
    103. ??
    104. ????????keyMap.put(PUBLIC_KEY,?publicKey);??
    105. ????????keyMap.put(PRIVATE_KEY,?privateKey);??
    106. ??
    107. ????????return?keyMap;??
    108. ????}??
    109. ??
    110. ????/**?
    111. ?????*?加密<br>?
    112. ?????*??
    113. ?????*?@param?data?
    114. ?????*????????????待加密数据?
    115. ?????*?@param?publicKey?
    116. ?????*????????????甲方公钥?
    117. ?????*?@param?privateKey?
    118. ?????*????????????乙方私钥?
    119. ?????*?@return?
    120. ?????*?@throws?Exception?
    121. ?????*/??
    122. ????public?static?byte[]?encrypt(byte[]?data,?String?publicKey,??
    123. ????????????String?privateKey)?throws?Exception?{??
    124. ??
    125. ????????//?生成本地密钥??
    126. ????????SecretKey?secretKey?=?getSecretKey(publicKey,?privateKey);??
    127. ??
    128. ????????//?数据加密??
    129. ????????Cipher?cipher?=?Cipher.getInstance(secretKey.getAlgorithm());??
    130. ????????cipher.init(Cipher.ENCRYPT_MODE,?secretKey);??
    131. ??
    132. ????????return?cipher.doFinal(data);??
    133. ????}??
    134. ??
    135. ????/**?
    136. ?????*?解密<br>?
    137. ?????*??
    138. ?????*?@param?data?
    139. ?????*????????????待解密数据?
    140. ?????*?@param?publicKey?
    141. ?????*????????????乙方公钥?
    142. ?????*?@param?privateKey?
    143. ?????*????????????乙方私钥?
    144. ?????*?@return?
    145. ?????*?@throws?Exception?
    146. ?????*/??
    147. ????public?static?byte[]?decrypt(byte[]?data,?String?publicKey,??
    148. ????????????String?privateKey)?throws?Exception?{??
    149. ??
    150. ????????//?生成本地密钥??
    151. ????????SecretKey?secretKey?=?getSecretKey(publicKey,?privateKey);??
    152. ????????//?数据解密??
    153. ????????Cipher?cipher?=?Cipher.getInstance(secretKey.getAlgorithm());??
    154. ????????cipher.init(Cipher.DECRYPT_MODE,?secretKey);??
    155. ??
    156. ????????return?cipher.doFinal(data);??
    157. ????}??
    158. ??
    159. ????/**?
    160. ?????*?构建密钥?
    161. ?????*??
    162. ?????*?@param?publicKey?
    163. ?????*????????????公钥?
    164. ?????*?@param?privateKey?
    165. ?????*????????????私钥?
    166. ?????*?@return?
    167. ?????*?@throws?Exception?
    168. ?????*/??
    169. ????private

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