RSA密钥生成、加密解密、数据签名验签

拼搏现实的明天。 2022-06-07 04:47 432阅读 0赞

*   *   *  公钥、私钥生成
            
             *  准备工作，基础的帮助类
             *  使用java代码生成公钥私钥
             *  使用openssl生成公钥私钥
         *  加解密
         *  数据签名及验签
         *  数据加解密及签名验签测试
         *  注意项

### 公钥、私钥生成 ###

#### 准备工作，基础的帮助类 ####

* **base64的数据帮助类** 
 代码依赖jar包[javabase64-1.3.1.jar][]
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 
 import it.sauronsoftware.base64.Base64;
 
 /** */
 /** * * BASE64编码解码工具包 * * * 依赖javabase64-1.3.1.jar * * */
 public class Base64Utils { 
 
 /** */
 /** * 文件读取缓冲区大小 */
 private static final int CACHE_SIZE = 1024;
 
 /** */
 /** * * BASE64字符串解码为二进制数据 * * * @param base64 * @return * @throws Exception */
 public static byte[] decode(String base64) throws Exception
 {
 return Base64.decode(base64.getBytes());
 }
 
 /** */
 /** * * 二进制数据编码为BASE64字符串 * * * @param bytes * @return * @throws Exception */
 public static String encode(byte[] bytes) throws Exception
 {
 return new String(Base64.encode(bytes));
 }
 
 /** */
 /** * * 将文件编码为BASE64字符串 * * * 大文件慎用，可能会导致内存溢出 * * * @param filePath * 文件绝对路径 * @return * @throws Exception */
 public static String encodeFile(String filePath) throws Exception
 {
 byte[] bytes = fileToByte(filePath);
 return encode(bytes);
 }
 
 /** */
 /** * * BASE64字符串转回文件 * * * @param filePath * 文件绝对路径 * @param base64 * 编码字符串 * @throws Exception */
 public static void decodeToFile(String filePath, String base64) throws Exception
 {
 byte[] bytes = decode(base64);
 byteArrayToFile(bytes, filePath);
 }
 
 /** */
 /** * * 文件转换为二进制数组 * * * @param filePath * 文件路径 * @return * @throws Exception */
 public static byte[] fileToByte(String filePath) throws Exception
 {
 byte[] data = new byte[0];
 File file = new File(filePath);
 if (file.exists())
 {
 FileInputStream in = new FileInputStream(file);
 ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
 byte[] cache = new byte[CACHE_SIZE];
 int nRead = 0;
 while ((nRead = in.read(cache)) != -1)
 {
 out.write(cache, 0, nRead);
 out.flush();
 }
 out.close();
 in.close();
 data = out.toByteArray();
 }
 return data;
 }
 
 /** */
 /** * * 二进制数据写文件 * * * @param bytes * 二进制数据 * @param filePath * 文件生成目录 */
 public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception
 {
 InputStream in = new ByteArrayInputStream(bytes);
 File destFile = new File(filePath);
 if (!destFile.getParentFile().exists())
 {
 destFile.getParentFile().mkdirs();
 }
 destFile.createNewFile();
 OutputStream out = new FileOutputStream(destFile);
 byte[] cache = new byte[CACHE_SIZE];
 int nRead = 0;
 while ((nRead = in.read(cache)) != -1)
 {
 out.write(cache, 0, nRead);
 out.flush();
 }
 out.close();
 in.close();
 }
 
 }
 * byte数组及hex转换帮助类
 
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 
 /** * byte[] hex数据帮助类 * * @author lupf * */
 public class ByteUtil
 {
 
 static byte[] mask = new byte[128];
 
 static
 {
 initMask();
 }
 static byte[] asciiMask = new byte[]
 { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
 
 private static void initMask()
 { // init mask
 for (int i = 0; i <= 9; i++)
 {
 mask[i + 48] = (byte) i;
 }
 for (int i = 0; i <= 5; i++)
 {
 mask[i + 97] = (byte) (10 + i);
 }
 for (int i = 0; i <= 5; i++)
 {
 mask[i + 65] = (byte) (10 + i);
 }
 }
 
 public static int[] byte2Bitmap(int b)
 {
 int[] bitmap = new int[8];
 for (int i = 0; i < 8; i++)
 {
 bitmap[i] = ((b >> (8 - i - 1)) & 0x01);
 }
 return bitmap;
 }
 
 public static byte[] intToBCD(int n, int balen)
 {
 byte[] ret = new byte[balen];
 int tmp;
 for (int i = 1; i <= balen; i++)
 {
 tmp = n % 100;
 ret[balen - i] = (byte) (tmp / 10 * 16 + tmp % 10);
 
 n -= tmp;
 if (n == 0)
 {
 break;
 }
 n /= 100;
 }
 return ret;
 }
 
 public static int bcdToInt(byte[] ba, int idx, int len)
 {
 int jinwei = len * 2;
 int ret = 0;
 int temp = 0;
 int pow;
 int posNum; // 正数
 for (int i = 0, n = len; i < n; i++)
 {
 pow = pow(10, (jinwei - 1));
 posNum = ba[idx + i] >= 0 ? ba[idx + i] : ba[idx + i] + 256;
 temp = (posNum / 16) * pow + posNum % 16 * pow / 10;
 ret += temp;
 jinwei -= 2;
 }
 return ret;
 }
 
 public static int pow(int x, int y)
 {
 int n = x;
 for (int i = 1; i < y; i++)
 {
 n *= x;
 }
 return n;
 }
 
 public static byte[] hexStr2Byte(String hex)
 {
 int len = (hex.length() / 2);
 byte[] result = new byte[len];
 char[] achar = hex.toCharArray();
 for (int i = 0; i < len; i++)
 {
 int pos = i * 2;
 result[i] = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
 }
 return result;
 }
 
 public static int revAsciiHexToInt(byte[] ah)
 {
 int ret = 0;
 for (int i = 0; i < ah.length / 2; i++)
 {
 int hex = (mask[ah[i * 2]] << 4) + (mask[ah[i * 2 + 1]]);
 ret += (hex << (8 * i));
 }
 return ret;
 }
 
 public static int revHexToInt(byte[] data, int off, int len)
 {
 int ret = 0;
 for (int i = 0; i < len; i++)
 {
 ret += (data[off + i] & 0xff) << (8 * i);
 }
 
 return ret;
 }
 
 public static int revAsciiHexToInt(byte[] ah, int off, int len)
 {
 int ret = 0;
 for (int i = 0, n = len / 2; i < n; i++)
 {
 int hex = (mask[ah[i * 2 + off]] << 4) + (mask[ah[i * 2 + off + 1]]);
 ret += (hex << (8 * i));
 }
 return ret;
 }
 
 public static byte[] intToRevAsciiHex(int value, int hexlen)
 {
 byte[] ret = new byte[hexlen * 2];
 
 for (int i = 0; i < hexlen; i++)
 {
 if (value > 0)
 {
 ret[i * 2] = asciiMask[((value & 0xf0) >> 4)];
 ret[i * 2 + 1] = asciiMask[(value & 0xf)];
 value >>= 8;
 }
 else
 {
 ret[i * 2] = '0';
 ret[i * 2 + 1] = '0';
 }
 }
 return ret;
 }
 
 public static String intToRevHexString(int value, int hexlen)
 {
 
 byte[] ret = new byte[hexlen];
 for (int i = 0; i < hexlen; i++)
 {
 ret[i] = (byte) (value & 0xff);
 value >>= 8;
 if (value == 0)
 break;
 }
 return hexToStr(ret);
 }
 
 public static byte[] intToAsciiHex(int value, int len)
 {
 byte[] ret = new byte[len * 2];
 for (int i = 0; i < len; i++)
 {
 ret[i * 2] = asciiMask[((value & 0xf0) >> 4)];
 ret[i * 2 + 1] = asciiMask[value & 0xf];
 value >>= 8;
 }
 return ret;
 }
 
 public static byte[] intToHex(int value, int len)
 {
 byte[] ret = new byte[len];
 for (int i = 0; i < len; i++)
 {
 ret[i] = (byte) ((value >> 8 * (len - i - 1)) & 0xff);
 }
 return ret;
 }
 
 public static byte[] intToRevHex(int value, int len)
 {
 byte[] ret = new byte[len];
 for (int i = 0; i < len; i++)
 {
 ret[i] = (byte) (value & 0xff);
 value >>= 8;
 }
 return ret;
 }
 
 public static int hexToInt(byte[] buf, int idx, int len)
 {
 int ret = 0;
 
 final int e = idx + len;
 for (int i = idx; i < e; ++i)
 {
 ret <<= 8;
 ret |= buf[i] & 0xFF;
 }
 return ret;
 }
 
 public static int hexToInt(byte[] buf)
 {
 return hexToInt(buf, 0, buf.length);
 }
 
 public static String hexToStr(byte[] buf)
 {
 return hexToStr(buf, 0, buf.length);
 }
 
 public static String hexToStr(byte[] buf, int idx, int len)
 {
 StringBuffer sb = new StringBuffer();
 int n;
 for (int i = 0; i < len; i++)
 {
 n = buf[i + idx] & 0xff;
 if (n < 0x10)
 {
 sb.append("0");
 }
 sb.append(Integer.toHexString(n));
 }
 
 return sb.toString();
 }
 
 private static byte toByte(char c)
 {
 return mask[c];
 }
 
 public static String strToHex(String str)
 {
 try
 {
 byte[] bytes = str.getBytes("GBK");
 StringBuilder sb = new StringBuilder(bytes.length * 2);
 // 转换hex编码
 for (byte b : bytes)
 {
 sb.append(Integer.toHexString(b + 0x800).substring(1));
 }
 return sb.toString();
 }
 catch (Exception e)
 {
 e.printStackTrace();
 }
 return null;
 }
 
 }

#### **使用java代码生成公钥私钥** ####

/** * 随机生成密钥对 * * @param filePath * 本地用于存放密钥的路径，如E:/rsa/;那么生成的密钥就会保存在指定的路径下 */
        public static void genKeyPair(String filePath)
        {
            // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
            File file = new File(filePath);
            if (!file.exists())
                file.mkdirs();
    
            KeyPairGenerator keyPairGen = null;
            try
            {
                keyPairGen = KeyPairGenerator.getInstance("RSA");
            }
            catch (NoSuchAlgorithmException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            // 初始化密钥对生成器，密钥大小
            keyPairGen.initialize(1024, new SecureRandom());
            // 生成一个密钥对，保存在keyPair中
            KeyPair keyPair = keyPairGen.generateKeyPair();
            // 得到私钥
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
            // 得到公钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
            try
            {
                // 得到公钥字符串
                String publicKeyString = Base64Utils.encode(publicKey.getEncoded());
                // 得到私钥字符串
                String privateKeyString = Base64Utils.encode(privateKey.getEncoded());
                // 将密钥对写入到文件
                FileWriter pubfw = new FileWriter(filePath + "/publicKey.keystore");
                FileWriter prifw = new FileWriter(filePath + "/privateKey.keystore");
                BufferedWriter pubbw = new BufferedWriter(pubfw);
                BufferedWriter pribw = new BufferedWriter(prifw);
                pubbw.write(publicKeyString);
                pribw.write(privateKeyString);
                pubbw.flush();
                pubbw.close();
                pubfw.close();
                pribw.flush();
                pribw.close();
                prifw.close();
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }

执行以上代码，即可在指定的文件目录下得到我们需要的公钥及私钥，如下图:  
![SouthEast][]

#### **使用openssl生成公钥私钥** ####

*  **资源下载**  
    这里的openssl是下载的支付宝开放平台下共享的资源，[下载入口][Link 1]，进入之后有如下的界面，这里下载的window的版本：  
    ![SouthEast 1][]  
    或者[百度云下载][Link 2]  
    解压之后，进入到openssl目录,如下图:  
    ![SouthEast 2][]
 *  **密钥生成**
    
     *  第一步：运行“**生成公钥私钥转换PCKS8.bat**”
     *  第二步：运行“**私钥转换PCKS8.bat**”
     *  第三步：同级目录下会出现下图中三个文件  
        ![SouthEast 3][]  
        红框中的2个文件即对应的公钥和私钥，使用notepad++或者UE查看即可。
     *  第四步：需注意以下情况  
        通过此方法生成的密钥是以下形式的  
        `-----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDP0TVM3bg80cqhA1XcqLCEi3MQ bWZYf5Zmwd2mA1C5DbNR1OtsPqemJsJkdTDx4OSuvvUhxHEXJbNPoWx+1ktV+5Cv hiytGjwQ5OKWOw9+Iq4Q10IzucgiKMe2NVDK1j9TnNK5SteSw+TUUgaNKS+hNPUq vX5jhQDvadE51JIO5wIDAQAB -----END PUBLIC KEY-----`  
        其中—–BEGIN PUBLIC KEY—–和—–END PUBLIC KEY—–为密钥的头和尾，实际使用过程中该部分需要去掉，实际的密钥如下：  
        `MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDP0TVM3bg80cqhA1XcqLCEi3MQbWZYf5Zmwd2mA1C5DbNR1OtsPqemJsJkdTDx4OSuvvUhxHEXJbNPoWx+1ktV+5CvhiytGjwQ5OKWOw9+Iq4Q10IzucgiKMe2NVDK1j9TnNK5SteSw+TUUgaNKS+hNPUqvX5jhQDvadE51JIO5wIDAQAB`

### **加解密** ###

这里的加解密使用的是通过java代码生成的密钥进行操作及测试

import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.security.InvalidKeyException;
 import java.security.KeyFactory;
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 
 import java.security.interfaces.RSAPrivateKey;
 import java.security.interfaces.RSAPublicKey;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.security.spec.X509EncodedKeySpec;
 
 import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
 import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.NoSuchPaddingException;
 
 public class RSAEncrypt { 
 /** * 字节数据转字符串专用集合 */
 private static final char[] HEX_CHAR =
 { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
 
 /** * 随机生成密钥对 * * @param filePath * 本地用于存放密钥的路径，如E:/rsa/;那么生成的密钥就会保存在指定的路径下 */
 public static void genKeyPair(String filePath)
 {
 // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
 File file = new File(filePath);
 if (!file.exists())
 file.mkdirs();
 
 KeyPairGenerator keyPairGen = null;
 try
 {
 keyPairGen = KeyPairGenerator.getInstance("RSA");
 }
 catch (NoSuchAlgorithmException e)
 {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 // 初始化密钥对生成器，密钥大小为96-1024位
 keyPairGen.initialize(1024, new SecureRandom());
 // 生成一个密钥对，保存在keyPair中
 KeyPair keyPair = keyPairGen.generateKeyPair();
 // 得到私钥
 RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
 // 得到公钥
 RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
 try
 {
 // 得到公钥字符串
 String publicKeyString = Base64Utils.encode(publicKey.getEncoded());
 // 得到私钥字符串
 String privateKeyString = Base64Utils.encode(privateKey.getEncoded());
 // 将密钥对写入到文件
 FileWriter pubfw = new FileWriter(filePath + "/publicKey.keystore");
 FileWriter prifw = new FileWriter(filePath + "/privateKey.keystore");
 BufferedWriter pubbw = new BufferedWriter(pubfw);
 BufferedWriter pribw = new BufferedWriter(prifw);
 pubbw.write(publicKeyString);
 pribw.write(privateKeyString);
 pubbw.flush();
 pubbw.close();
 pubfw.close();
 pribw.flush();
 pribw.close();
 prifw.close();
 }
 catch (Exception e)
 {
 e.printStackTrace();
 }
 }
 
 /** * 从文件中输入流中加载公钥 * * @param in * 公钥输入流 * @throws Exception * 加载公钥时产生的异常 */
 public static String loadPublicKeyByFile(String path) throws Exception
 {
 try
 {
 BufferedReader br = new BufferedReader(new FileReader(path + "/publicKey.keystore"));
 String readLine = null;
 StringBuilder sb = new StringBuilder();
 while ((readLine = br.readLine()) != null)
 {
 sb.append(readLine);
 }
 br.close();
 return sb.toString();
 }
 catch (IOException e)
 {
 throw new Exception("公钥数据流读取错误");
 }
 catch (NullPointerException e)
 {
 throw new Exception("公钥输入流为空");
 }
 }
 
 /** * 从字符串中加载公钥 * * @param publicKeyStr * 公钥数据字符串 * @throws Exception * 加载公钥时产生的异常 */
 public static RSAPublicKey loadPublicKeyByStr(String publicKeyStr) throws Exception
 {
 try
 {
 byte[] buffer = Base64Utils.decode(publicKeyStr);
 KeyFactory keyFactory = KeyFactory.getInstance("RSA");
 X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
 return (RSAPublicKey) keyFactory.generatePublic(keySpec);
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此算法");
 }
 catch (InvalidKeySpecException e)
 {
 throw new Exception("公钥非法");
 }
 catch (NullPointerException e)
 {
 throw new Exception("公钥数据为空");
 }
 }
 
 /** * 从文件中加载私钥 * * @param keyFileName * 私钥文件名 * @return 是否成功 * @throws Exception */
 public static String loadPrivateKeyByFile(String path) throws Exception
 {
 try
 {
 BufferedReader br = new BufferedReader(new FileReader(path + "/privateKey.keystore"));
 String readLine = null;
 StringBuilder sb = new StringBuilder();
 while ((readLine = br.readLine()) != null)
 {
 sb.append(readLine);
 }
 br.close();
 return sb.toString();
 }
 catch (IOException e)
 {
 throw new Exception("私钥数据读取错误");
 }
 catch (NullPointerException e)
 {
 throw new Exception("私钥输入流为空");
 }
 }
 
 public static RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr) throws Exception
 {
 try
 {
 byte[] buffer = Base64Utils.decode(privateKeyStr);
 PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);
 KeyFactory keyFactory = KeyFactory.getInstance("RSA");
 return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此算法");
 }
 catch (InvalidKeySpecException e)
 {
 throw new Exception("私钥非法");
 }
 catch (NullPointerException e)
 {
 throw new Exception("私钥数据为空");
 }
 }
 
 /** * 公钥加密过程 * * @param publicKey * 公钥 * @param plainTextData * 明文数据 * @return * @throws Exception * 加密过程中的异常信息 */
 public static byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception
 {
 if (publicKey == null)
 {
 throw new Exception("加密公钥为空, 请设置");
 }
 Cipher cipher = null;
 try
 {
 // 使用默认RSA
 cipher = Cipher.getInstance("RSA");
 // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
 cipher.init(Cipher.ENCRYPT_MODE, publicKey);
 byte[] output = cipher.doFinal(plainTextData);
 return output;
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此加密算法");
 }
 catch (NoSuchPaddingException e)
 {
 e.printStackTrace();
 return null;
 }
 catch (InvalidKeyException e)
 {
 throw new Exception("加密公钥非法,请检查");
 }
 catch (IllegalBlockSizeException e)
 {
 throw new Exception("明文长度非法");
 }
 catch (BadPaddingException e)
 {
 throw new Exception("明文数据已损坏");
 }
 }
 
 /** * 私钥加密过程 * * @param privateKey * 私钥 * @param plainTextData * 明文数据 * @return * @throws Exception * 加密过程中的异常信息 */
 public static byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData) throws Exception
 {
 if (privateKey == null)
 {
 throw new Exception("加密私钥为空, 请设置");
 }
 Cipher cipher = null;
 try
 {
 // 使用默认RSA
 cipher = Cipher.getInstance("RSA");
 cipher.init(Cipher.ENCRYPT_MODE, privateKey);
 byte[] output = cipher.doFinal(plainTextData);
 return output;
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此加密算法");
 }
 catch (NoSuchPaddingException e)
 {
 e.printStackTrace();
 return null;
 }
 catch (InvalidKeyException e)
 {
 throw new Exception("加密私钥非法,请检查");
 }
 catch (IllegalBlockSizeException e)
 {
 throw new Exception("明文长度非法");
 }
 catch (BadPaddingException e)
 {
 throw new Exception("明文数据已损坏");
 }
 }
 
 /** * 私钥解密过程 * * @param privateKey * 私钥 * @param cipherData * 密文数据 * @return 明文 * @throws Exception * 解密过程中的异常信息 */
 public static byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception
 {
 if (privateKey == null)
 {
 throw new Exception("解密私钥为空, 请设置");
 }
 Cipher cipher = null;
 try
 {
 // 使用默认RSA
 cipher = Cipher.getInstance("RSA");
 // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
 cipher.init(Cipher.DECRYPT_MODE, privateKey);
 byte[] output = cipher.doFinal(cipherData);
 return output;
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此解密算法");
 }
 catch (NoSuchPaddingException e)
 {
 e.printStackTrace();
 return null;
 }
 catch (InvalidKeyException e)
 {
 throw new Exception("解密私钥非法,请检查");
 }
 catch (IllegalBlockSizeException e)
 {
 throw new Exception("密文长度非法");
 }
 catch (BadPaddingException e)
 {
 throw new Exception("密文数据已损坏");
 }
 }
 
 /** * 公钥解密过程 * * @param publicKey * 公钥 * @param cipherData * 密文数据 * @return 明文 * @throws Exception * 解密过程中的异常信息 */
 public static byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData) throws Exception
 {
 if (publicKey == null)
 {
 throw new Exception("解密公钥为空, 请设置");
 }
 Cipher cipher = null;
 try
 {
 // 使用默认RSA
 cipher = Cipher.getInstance("RSA");
 // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
 cipher.init(Cipher.DECRYPT_MODE, publicKey);
 byte[] output = cipher.doFinal(cipherData);
 return output;
 }
 catch (NoSuchAlgorithmException e)
 {
 throw new Exception("无此解密算法");
 }
 catch (NoSuchPaddingException e)
 {
 e.printStackTrace();
 return null;
 }
 catch (InvalidKeyException e)
 {
 throw new Exception("解密公钥非法,请检查");
 }
 catch (IllegalBlockSizeException e)
 {
 throw new Exception("密文长度非法");
 }
 catch (BadPaddingException e)
 {
 throw new Exception("密文数据已损坏");
 }
 }
 
 /** * 字节数据转十六进制字符串 * * @param data * 输入数据 * @return 十六进制内容 */
 public static String byteArrayToString(byte[] data)
 {
 StringBuilder stringBuilder = new StringBuilder();
 for (int i = 0; i < data.length; i++)
 {
 // 取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移
 stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]);
 // 取出字节的低四位 作为索引得到相应的十六进制标识符
 stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);
 if (i < data.length - 1)
 {
 stringBuilder.append(' ');
 }
 }
 return stringBuilder.toString();
 }
 }

### **数据签名及验签** ###

import java.security.KeyFactory;
    import java.security.PrivateKey;
    import java.security.PublicKey;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    
    /** * RSA签名验签类 */
    public class RSASignature { 
    
        /** * 签名算法 */
        public static final String SIGN_ALGORITHMS = "SHA1WithRSA";
    
        /** * RSA签名,得到base64字符串 * * @param content * 待签名数据 * @param privateKey * 商户私钥 * @param encode * 字符集编码 * @return 签名值,base64字符串 */
        public static String signBase64(String content, String privateKey, String encode)
        {
            try
            {
                PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64Utils.decode(privateKey));
    
                KeyFactory keyf = KeyFactory.getInstance("RSA");
                PrivateKey priKey = keyf.generatePrivate(priPKCS8);
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initSign(priKey);
                signature.update(content.getBytes(encode));
    
                byte[] signed = signature.sign();
    
                return Base64Utils.encode(signed);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return null;
        }
    
        /** * RSA签名,得到base64字符串 * * @param content * 待签名数据 * @param privateKey * 商户私钥 * @return 签名值,base64字符串 */
        public static String signBase64(String content, String privateKey)
        {
            try
            {
                PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64Utils.decode(privateKey));
                KeyFactory keyf = KeyFactory.getInstance("RSA");
                PrivateKey priKey = keyf.generatePrivate(priPKCS8);
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
                signature.initSign(priKey);
                signature.update(content.getBytes());
                byte[] signed = signature.sign();
                return Base64Utils.encode(signed);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
            return null;
        }
    
        /** * RSA验签名检查,数据源为base64字符串 * * @param content * 待签名数据,base64字符串 * @param sign * 签名值 * @param publicKey * 分配给开发商公钥 * @param encode * 字符集编码 * @return 布尔值 */
        public static boolean doCheckBase64(String content, String sign, String publicKey, String encode)
        {
            try
            {
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                byte[] encodedKey = Base64Utils.decode(publicKey);
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initVerify(pubKey);
                signature.update(content.getBytes(encode));
    
                boolean bverify = signature.verify(Base64Utils.decode(sign));
                return bverify;
    
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return false;
        }
    
        /** * RSA验签名检查,数据源为base64字符串 * * @param content * 待签名数据,base64字符串 * @param sign * 签名值 * @param publicKey * 分配给开发商公钥 * @return 布尔值 */
        public static boolean doCheckBase64(String content, String sign, String publicKey)
        {
            try
            {
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                byte[] encodedKey = Base64Utils.decode(publicKey);
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initVerify(pubKey);
                signature.update(content.getBytes());
    
                boolean bverify = signature.verify(Base64Utils.decode(sign));
                return bverify;
    
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return false;
        }
    
        /** * RSA签名,得到Hex字符串 * * @param content * 待签名数据 * @param privateKey * 商户私钥 * @param encode * 字符集编码 * @return 签名值,Hex字符串 */
        public static String signHex(String content, String privateKey, String encode)
        {
            try
            {
                PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64Utils.decode(privateKey));
    
                KeyFactory keyf = KeyFactory.getInstance("RSA");
                PrivateKey priKey = keyf.generatePrivate(priPKCS8);
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initSign(priKey);
                signature.update(content.getBytes(encode));
                byte[] signed = signature.sign();
                return ByteUtil.hexToStr(signed);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return null;
        }
    
        /** * RSA签名,得到Hex字符串 * * @param content * 待签名数据 * @param privateKey * 商户私钥 * @return 签名值,Hex字符串 */
        public static String signHex(String content, String privateKey)
        {
            try
            {
                PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64Utils.decode(privateKey));
                KeyFactory keyf = KeyFactory.getInstance("RSA");
                PrivateKey priKey = keyf.generatePrivate(priPKCS8);
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
                signature.initSign(priKey);
                signature.update(content.getBytes());
                byte[] signed = signature.sign();
                return ByteUtil.hexToStr(signed);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
            return null;
        }
    
        /** * RSA验签名检查,数据源为Hex字符串 * * @param content * 待签名数据,Hex字符串 * @param sign * 签名值 * @param publicKey * 分配给开发商公钥 * @param encode * 字符集编码 * @return 布尔值 */
        public static boolean doCheckHex(String content, String sign, String publicKey, String encode)
        {
            try
            {
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                byte[] encodedKey = Base64Utils.decode(publicKey);
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initVerify(pubKey);
                signature.update(content.getBytes(encode));
    
                boolean bverify = signature.verify(ByteUtil.hexStr2Byte(sign));
                return bverify;
    
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return false;
        }
    
        /** * RSA验签名检查,数据源为Hex字符串 * * @param content * 待签名数据,Hex字符串 * @param sign * 签名值 * @param publicKey * 分配给开发商公钥 * @return 布尔值 */
        public static boolean doCheckHex(String content, String sign, String publicKey)
        {
            try
            {
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                byte[] encodedKey = Base64Utils.decode(publicKey);
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
    
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
    
                signature.initVerify(pubKey);
                signature.update(content.getBytes());
    
                boolean bverify = signature.verify(ByteUtil.hexStr2Byte(sign));
                return bverify;
    
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
    
            return false;
        }
    }

### **数据加解密及签名验签测试** ###

public class MainTest
    {
        public static void main(String[] args)
        {
            try
            {
                String filepath = "E:/rsa/";
    
                RSAEncrypt.genKeyPair(filepath);
    
                String privateKey = RSAEncrypt.loadPrivateKeyByFile(filepath);
                String publicKey = RSAEncrypt.loadPublicKeyByFile(filepath);
    
                System.out.println("私钥：" + privateKey);
                System.out.println("公钥：" + publicKey);
    
                System.out.println("--------------公钥加密私钥解密过程-------------------");
                String data = "rsa公钥加密私钥解密过程";
                // 公钥加密过程
                byte[] cipherData = RSAEncrypt.encrypt(RSAEncrypt.loadPublicKeyByStr(publicKey), data.getBytes());
                // base64的密文数据
                String cipher = Base64Utils.encode(cipherData);
                // hex的密文数据
                String cipherHex = ByteUtil.hexToStr(cipherData);
                // 私钥解密base64的密文过程
                byte[] resBase64 = RSAEncrypt.decrypt(RSAEncrypt.loadPrivateKeyByStr(privateKey), Base64Utils.decode(cipher));
                String restrBase64 = new String(resBase64);
    
                // 私钥解密hex的密文过程
                byte[] resHex = RSAEncrypt.decrypt(RSAEncrypt.loadPrivateKeyByStr(privateKey), ByteUtil.hexStr2Byte(cipherHex));
                String restrHex = new String(resHex);
    
                System.out.println("原文：" + data);
                System.out.println("加密(base64)：" + cipher);
                System.out.println("加密(hex)：" + cipherHex);
                System.out.println("解密(base64)：" + restrBase64);
                System.out.println("解密(hex)：" + restrHex);
                System.out.println();
    
                System.out.println("--------------私钥加密公钥解密过程-------------------");
                data = "rsa私钥加密公钥解密过程";
                // 私钥加密过程
                cipherData = RSAEncrypt.encrypt(RSAEncrypt.loadPrivateKeyByStr(privateKey), data.getBytes());
                cipher = Base64Utils.encode(cipherData);
                // 公钥解密过程
                resBase64 = RSAEncrypt.decrypt(RSAEncrypt.loadPublicKeyByStr(publicKey), Base64Utils.decode(cipher));
                restrBase64 = new String(resBase64);
                System.out.println("原文：" + data);
                System.out.println("加密：" + cipher);
                System.out.println("解密：" + restrBase64);
                System.out.println();
    
                System.out.println("--------------签名及验签测试-----------------------");
                data = "rsa签名及验签测试";
    
                System.out.println("签名源数据:" + data);
                String singData = RSASignature.signBase64(data, privateKey);
                System.out.println("使用私钥对data数据签名,得到base64的签名数据为:" + singData);
                boolean ckeckVa = RSASignature.doCheckBase64(data, singData, publicKey);
                System.out.println("使用公钥对签名后的base64数据进行验证的结果为:" + ckeckVa);
    
                System.out.println("");
    
                singData = RSASignature.signHex(data, privateKey);
                System.out.println("使用私钥对data数据签名,得到hex的签名数据为:" + singData);
                ckeckVa = RSASignature.doCheckHex(data, singData, publicKey);
                System.out.println("使用公钥对签名后的hex数据进行验证的结果为:" + ckeckVa);
            }
            catch (Exception e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

运行结果如下图:  
![SouthEast 4][]

--------------------

到这里rsa密钥的生成，加密解密就完了

--------------------

### **注意项** ###

rsa目前只能加密117字节；解密118字节的数据，如果数据太长，不太适合使用rsa加密方式；可以考虑使用对称加密；然后将对称加密的密钥使用rsa加密；然后将加密后的密钥对数据进行加密。

[javabase64-1.3.1.jar]: http://pan.baidu.com/s/1dEKayAH
[SouthEast]: /images/20220607/c36a3f56823d4289bf88b0d73d950cc2.png
[Link 1]: https://docs.open.alipay.com/58/103242
[SouthEast 1]: /images/20220607/8172b72ca8c1444e925cf2f7e17e6535.png
[Link 2]: http://pan.baidu.com/s/1eSiuQuI
[SouthEast 2]: /images/20220607/15d1c6adaee1406f91249f363778b319.png
[SouthEast 3]: /images/20220607/311aefd2d82147c88008cc157e4d870d.png
[SouthEast 4]: /images/20220607/433f82ff461e4d089acad477e0d47497.png