首先 有服務端生產一對公鑰和私鑰 我們在進行加密之前，先從服務器獲取公鑰，獲取到公鑰串之后，在對密碼進行加密。
此處，就是在登陸之前，對密碼進行加密
password：登錄密碼 rsastr：從服務器獲取的公鑰串
Hex.encodeHex：對加密后的密碼串進行編碼，項目中需要集成相應的jar。
下面給出 RSAUtils的代碼
import java.io.ByteArrayOutputStream;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;/** * <p> * RSA公鑰/私鑰/簽名工具包 * </p> * <p> * 羅納德·李維斯特（Ron [R]ivest）、阿迪·薩莫爾（Adi [S]hamir）和倫納德·阿德曼（Leonard [A]dleman） * </p> * <p> * 字符串格式的密鑰在未在特殊說明情況下都為BASE64編碼格式<br/> * 由于非對稱加密速度極其緩慢，一般文件不使用它來加密而是使用對稱加密，<br/> * 非對稱加密算法可以用來對對稱加密的密鑰加密，這樣保證密鑰的安全也就保證了數據的安全 * </p> * * @author IceWee * @version 1.0 * @date 2012-4-26 */public class RSAUtils { /** * 加密算法RSA */ public static final String KEY_ALGORITHM = "RSA"; /** * 簽名算法 */ public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; /** * 獲取公鑰的key */ private static final String PUBLIC_KEY = "RSAPublicKey"; /** * 獲取私鑰的key */ private static final String PRIVATE_KEY = "RSAPrivateKey"; /** * RSA最大加密明文大小 */ private static final int MAX_ENCRYPT_BLOCK = 117; /** * RSA最大解密密文大小 */ private static final int MAX_DECRYPT_BLOCK = 128; /** * <p> * 生成密鑰對(公鑰和私鑰) * </p> * * @return * @throws Exception */ public static Map<String, Object> genKeyPair() throws Exception { KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM); keyPairGen.initialize(1024); KeyPair keyPair = keyPairGen.generateKeyPair(); RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); 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; } /** * <p> * 用私鑰對信息生成數字簽名 * </p> * * @param data 已加密數據 * @param privateKey 私鑰(BASE64編碼) * @return * @throws Exception */ public static String sign(byte[] data, String privateKey) throws Exception { byte[] keyBytes = Base64Utils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initSign(privateK); signature.update(data); return Base64Utils.encode(signature.sign()); } /** * <p> * 校驗數字簽名 * * </p> * * @param data 已加密數據 * @param publicKey 公鑰(BASE64編碼) * @param sign 數字簽名 * @return * @throws Exception */ public static boolean verify(byte[] data, String publicKey, String sign) throws Exception { byte[] keyBytes = Base64Utils.decode(publicKey); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PublicKey publicK = keyFactory.generatePublic(keySpec); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initVerify(publicK); signature.update(data); return signature.verify(Base64Utils.decode(sign)); } /** * <P> * 私鑰解密 * </p> * * @param encryptedData 已加密數據 * @param privateKey 私鑰(BASE64編碼) * @return * @throws Exception */ public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception { byte[] keyBytes = Base64Utils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);// Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.DECRYPT_MODE, privateK); int inputLen = encryptedData.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 對數據分段解密 while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_DECRYPT_BLOCK) { cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK); } else { cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_DECRYPT_BLOCK; } byte[] decryptedData = out.toByteArray(); out.close(); return decryptedData; } /** * <p> * 公鑰解密 * </p> * * @param encryptedData 已加密數據 * @param publicKey 公鑰(BASE64編碼) * @return * @throws Exception */ public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception { byte[] keyBytes = Base64Utils.decode(publicKey); X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicK = keyFactory.generatePublic(x509KeySpec);// Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.DECRYPT_MODE, publicK); int inputLen = encryptedData.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 對數據分段解密 while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_DECRYPT_BLOCK) { cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK); } else { cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_DECRYPT_BLOCK; } byte[] decryptedData = out.toByteArray(); out.close(); return decryptedData; } /** * <p> * 公鑰加密 * </p> * * @param sourcedata 源數據 * @param publicKey 公鑰(BASE64編碼) * @return * @throws Exception */ public static byte[] encryptByPublicKey(String sourcedata, String publicKey) throws Exception { byte[] data = sourcedata.getBytes(); byte[] keyBytes = Base64Utils.decode(publicKey); X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicK = keyFactory.generatePublic(x509KeySpec); // 對數據加密// Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.ENCRYPT_MODE, publicK); int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 對數據分段加密 while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_ENCRYPT_BLOCK) { cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK); } else { cache = cipher.doFinal(data, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_ENCRYPT_BLOCK; } byte[] encryptedData = out.toByteArray(); out.close(); return encryptedData; } /** * <p> * 私鑰加密 * </p> * * @param data 源數據 * @param privateKey 私鑰(BASE64編碼) * @return * @throws Exception */ public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception { byte[] keyBytes = Base64Utils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);// Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.ENCRYPT_MODE, privateK); int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 對數據分段加密 while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_ENCRYPT_BLOCK) { cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK); } else { cache = cipher.doFinal(data, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_ENCRYPT_BLOCK; } byte[] encryptedData = out.toByteArray(); out.close(); return encryptedData; } /** * <p> * 獲取私鑰 * </p> * * @param keyMap 密鑰對 * @return * @throws Exception */ public static String getPrivateKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PRIVATE_KEY); return Base64Utils.encode(key.getEncoded()); } /** * <p> * 獲取公鑰 * </p> * * @param keyMap 密鑰對 * @return * @throws Exception */ public static String getPublicKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PUBLIC_KEY); return Base64Utils.encode(key.getEncoded()); } // 把byte[]元素之間添加空格，并轉化成字符串返回， public static String byteToString(byte[] resouce){ StringBuffer sb = new StringBuffer(); for (int i = 0; i < resouce.length; i++) { if (i == resouce.length-1) { sb.append(Byte.toString(resouce[i])); }else{ sb.append(Byte.toString(resouce[i])); sb.append(" "); } } return sb.toString(); } // 把字符串按照空格進行拆分成數組，然后轉化成byte[],返回 public static byte[] stringToByte(String resouce){ String[] strArr = resouce.split(" "); int len = strArr.length; byte[] clone = new byte[len]; for (int i = 0; i < len; i++) { clone[i] = Byte.parseByte(strArr[i]); } return clone; }}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
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