java 加密算法的代码实现

package rsa; import java.security.Key; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.PrivateKey; import java.security.PublicKey; import java.security.Signature; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.HashMap; import java.util.Map; import javax.crypto.Cipher; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; /** * RSA安全编码组件 * * @version 1.0 * @since 1.0 */ public class RSACoder { public static final String KEY_ALGORITHM = "RSA"; public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; private static final String PUBLIC_KEY = "RSAPublicKey"; private static final String PRIVATE_KEY = "RSAPrivateKey"; /** *//** * 用私钥对信息生成数字签名 * * @param data * 加密数据 * @param privateKey * 私钥 * * @return * @throws Exception */ public static String sign(byte[] data, String privateKey) throws Exception { // 解密由base64编码的私钥 byte[] keyBytes = decryptBASE64(privateKey); // 构造PKCS8EncodedKeySpec对象 PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); // KEY_ALGORITHM 指定的加密算法 KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); // 取私钥匙对象 PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec); // 用私钥对信息生成数字签名 Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initSign(priKey); signature.update(data); return encryptBASE64(signature.sign()); } /** *//** * 校验数字签名 * * @param data * 加密数据 * @param publicKey * 公钥 * @param sign * 数字签名 * * @return 校验成功返回true 失败返回false * @throws Exception * */ public static boolean verify(byte[] data, String publicKey, String sign) throws Exception { // 解密由base64编码的公钥 byte[] keyBytes = decryptBASE64(publicKey); // 构造X509EncodedKeySpec对象 X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); // KEY_ALGORITHM 指定的加密算法 KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); // 取公钥匙对象 PublicKey pubKey = keyFactory.generatePublic(keySpec); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initVerify(pubKey); signature.update(data); // 验证签名是否正常 return signature.verify(decryptBASE64(sign)); } /** *//** * 解密<br> * 用私钥解密 http://www.5a520.cn http://www.feng123.com * * @param data * @param key * @return * @throws Exception */ public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception { // 对密钥解密 byte[] keyBytes = decryptBASE64(key); // 取得私钥 PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec); // 对数据解密 Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.DECRYPT_MODE, privateKey); return cipher.doFinal(data); } /** *//** * 解密<br> * 用私钥解密 * * @param data * @param key * @return * @throws Exception */ public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception { // 对密钥解密 byte[] keyBytes = decryptBASE64(key); // 取得公钥 X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicKey = keyFactory.generatePublic(x509KeySpec); // 对数据解密 Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.DECRYPT_MODE, publicKey); return cipher.doFinal(data); } /** *//** * 加密<br> * 用公钥加密 * * @param data * @param key * @return * @throws Exception */ public static byte[] encryptByPublicKey(byte[] data, String key) throws Exception { // 对公钥解密 byte[] keyBytes = decryptBASE64(key); // 取得公钥 X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicKey = keyFactory.generatePublic(x509KeySpec); // 对数据加密 Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.ENCRYPT_MODE, publicKey); return cipher.doFinal(data); } /** *//** * 加密<br> * 用私钥加密 * * @param data * @param key * @return * @throws Exception */ public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception { // 对密钥解密 byte[] keyBytes = decryptBASE64(key); // 取得私钥 PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec); // 对数据加密 Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.ENCRYPT_MODE, privateKey); return cipher.doFinal(data); } /** *//** * 取得私钥 * * @param keyMap * @return * @throws Exception */ public static String getPrivateKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PRIVATE_KEY); return encryptBASE64(key.getEncoded()); } /** *//** * 取得公钥 * * @param keyMap * @return * @throws Exception */ public static String getPublicKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PUBLIC_KEY); return encryptBASE64(key.getEncoded()); } /** *//** * 初始化密钥 * * @return * @throws Exception */ public static Map<String, Object> initKey() throws Exception { KeyPairGenerator keyPairGen = KeyPairGenerator .getInstance(KEY_ALGORITHM); keyPairGen.initialize(1024); KeyPair keyPair = keyPairGen.generateKeyPair(); // 公钥 RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 私钥 RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); Map<String, Object> keyMap = new HashMap<String, Object>(2); keyMap.put(PUBLIC_KEY, publicKey); keyMap.put(PRIVATE_KEY, privateKey); return keyMap; } public static byte[] decryptBASE64(String key) throws Exception { return (new BASE64Decoder()).decodeBuffer(key); } /** * BASE64加密