1 import java.io.ByteArrayInputStream; 2 import java.io.ByteArrayOutputStream; 3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileOutputStream; 6 import java.io.InputStream; 7 import java.io.OutputStream; 8 9 import it.sauronsoftware.base64.Base64; 10 public class Base64Utils{ 11 /** */ 12 /** 13 * 文件读取缓冲区大小 14 */ 15 private static final int CACHE_SIZE = 1024; 16 17 /** */ 18 /** 19 * <p> 20 * BASE64字符串解码为二进制数据 21 * </p> 22 * 23 * @param base64 24 * @return 25 * @throws Exception 26 */ 27 public static byte[] decode(String base64) throws Exception { 28 return Base64.decode(base64.getBytes("UTF-8")); 29 } 30 31 /** */ 32 /** 33 * <p> 34 * 二进制数据编码为BASE64字符串 35 * </p> 36 * 37 * @param bytes 38 * @return 39 * @throws Exception 40 */ 41 public static String encode(byte[] bytes) throws Exception { 42 return new String(Base64.encode(bytes)); 43 } 44 45 /** */ 46 /** 47 * <p> 48 * 将文件编码为BASE64字符串 49 * </p> 50 * <p> 51 * 大文件慎用，可能会导致内存溢出 52 * </p> 53 * 54 * @param filePath 55 * 文件绝对路径 56 * @return 57 * @throws Exception 58 */ 59 public static String encodeFile(String filePath) throws Exception { 60 byte[] bytes = fileToByte(filePath); 61 return encode(bytes); 62 } 63 64 /** */ 65 /** 66 * <p> 67 * BASE64字符串转回文件 68 * </p> 69 * 70 * @param filePath 71 * 文件绝对路径 72 * @param base64 73 * 编码字符串 74 * @throws Exception 75 */ 76 public static void decodeToFile(String filePath, String base64) throws Exception { 77 byte[] bytes = decode(base64); 78 byteArrayToFile(bytes, filePath); 79 } 80 81 /** */ 82 /** 83 * <p> 84 * 文件转换为二进制数组 85 * </p> 86 * 87 * @param filePath 88 * 文件路径 89 * @return 90 * @throws Exception 91 */ 92 public static byte[] fileToByte(String filePath) throws Exception { 93 byte[] data = new byte[0]; 94 File file = new File(filePath); 95 if (file.exists()) { 96 FileInputStream in = new FileInputStream(file); 97 ByteArrayOutputStream out = new ByteArrayOutputStream(2048); 98 byte[] cache = new byte[CACHE_SIZE]; 99 int nRead = 0; 100 while ((nRead = in.read(cache)) != -1) { 101 out.write(cache, 0, nRead); 102 out.flush(); 103 } 104 out.close(); 105 in.close(); 106 data = out.toByteArray(); 107 } 108 return data; 109 } 110 111 /** */ 112 /** 113 * <p> 114 * 二进制数据写文件 115 * </p> 116 * 117 * @param bytes 118 * 二进制数据 119 * @param filePath 120 * 文件生成目录 121 */ 122 public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception { 123 InputStream in = new ByteArrayInputStream(bytes); 124 File destFile = new File(filePath); 125 if (!destFile.getParentFile().exists()) { 126 destFile.getParentFile().mkdirs(); 127 } 128 destFile.createNewFile(); 129 OutputStream out = new FileOutputStream(destFile); 130 byte[] cache = new byte[CACHE_SIZE]; 131 int nRead = 0; 132 while ((nRead = in.read(cache)) != -1) { 133 out.write(cache, 0, nRead); 134 out.flush(); 135 } 136 out.close(); 137 in.close(); 138 } 139 140 } base64Utils
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; public class RSAUtils{ /** */ /** * 加密算法RSA */ public static final String KEY_ALGORITHM = "RSA"; /** */ /** * 签名算法 */ public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; /** */ /** * 获取公钥的key */ private static final String PUBLIC_KEY = "RSAPublicKey"; /** */ /** * 获取私钥的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> * 生成密钥对(公钥和私钥) * </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> * 用私钥对信息生成数字签名 * </p> * * @param data * 已加密数据 * @param privateKey * 私钥(BASE64编码) * * @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> * 校验数字签名 * </p> * * @param data * 已加密数据 * @param publicKey * 公钥(BASE64编码) * @param sign * 数字签名 * * @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> * 私钥解密 * </p> * * @param encryptedData * 已加密数据 * @param privateKey * 私钥(BASE64编码) * @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.init(Cipher.DECRYPT_MODE, privateK); int inputLen = encryptedData.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 对数据分段解密 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> * 公钥解密 * </p> * * @param encryptedData * 已加密数据 * @param publicKey * 公钥(BASE64编码) * @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.init(Cipher.DECRYPT_MODE, publicK); int inputLen = encryptedData.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 对数据分段解密 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> * 公钥加密 * </p> * * @param data * 源数据 * @param publicKey * 公钥(BASE64编码) * @return * @throws Exception */ public static byte[] encryptByPublicKey(byte[] data, 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); // 对数据加密 Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.ENCRYPT_MODE, publicK); int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 对数据分段加密 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> * 私钥加密 * </p> * * @param data * 源数据 * @param privateKey * 私钥(BASE64编码) * @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.init(Cipher.ENCRYPT_MODE, privateK); int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 对数据分段加密 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> * 获取私钥 * </p> * * @param keyMap * 密钥对 * @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> * 获取公钥 * </p> * * @param keyMap * 密钥对 * @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()); } /** * java端公钥加密 */ public static String encryptedDataOnJava(String data, String PUBLICKEY) { try { data = Base64Utils.encode(encryptByPublicKey(data.getBytes(), PUBLICKEY)); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return data; } /** * java端私钥解密 */ public static String decryptDataOnJava(String data, String PRIVATEKEY) { String temp = ""; try { byte[] rs = Base64Utils.decode(data); temp = new String(RSAUtils.decryptByPrivateKey(rs, PRIVATEKEY),"UTF-8"); //以utf-8的方式生成字符串 } catch (Exception e) { e.printStackTrace(); } return temp; } } rsa 获取公私钥 加解密 算法
来源：博客园
作者：闻长歌而知雅意
链接：https://www.cnblogs.com/assistants/p/11655134.html