项目背景:要对打印地址进行加密,用公钥加密后会乱码需要base64 decode一下,但是在解密时报错:javax.crypto.BadPaddingException: Data must start with zero
解决办法:
1.加解密时KeyFactory keyFactory = KeyFactory.getInstance("RSA");
2.将加解密的Cipher cipher = Cipher.getInstance(“RSA”)改为Cipher cipher = Cipher.getInstance(“RSA/ECB/NoPadding”)
困扰了两天的问题解决了,代码如下,希望有次问题的同学不必再走此弯路。
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package resources.util.encryption;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.security.Key;
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import java.security.KeyFactory;
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import java.security.KeyPair;
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import java.security.KeyPairGenerator;
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import java.security.PrivateKey;
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import java.security.PublicKey;
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import java.security.spec.PKCS8EncodedKeySpec;
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import java.security.spec.X509EncodedKeySpec;
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import javax.crypto.Cipher;
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import org.junit.Test;
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public class EncryptionUtil {
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private static final String RSA = "RSA";
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private static final String RSANOPADDING = "RSA/ECB/NoPadding";
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private static final String PUBLIC_KEY_PATH = "public.key";
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private static final String PRIVATE_KEY_PATH = "private.key";
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private static final String path = Thread.currentThread().getContextClassLoader().getResource("/").getPath();
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// private static final String path = "";
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@Test
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public void generateKey() throws Exception {
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//KeyPairGenerator引擎类用于产生密钥对,JDK(7)默认支持的算法有,DiffieHellman、DSA、RSA、EC
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KeyPairGenerator generator = KeyPairGenerator.getInstance(RSA);
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generator.initialize(512);
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//产生密钥对
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KeyPair keyPair = generator.generateKeyPair();
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//获取公钥
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PublicKey publicKey = keyPair.getPublic();
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//获取私钥
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PrivateKey privateKey = keyPair.getPrivate();
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//将公钥与私钥写入文件,以备后用
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writeKey(PUBLIC_KEY_PATH, publicKey);
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writeKey(PRIVATE_KEY_PATH, privateKey);
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}
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//公钥加密
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public byte[] SRAEncrypt(String src) throws Exception {
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PublicKey publicKey= (PublicKey)readKey(path + PUBLIC_KEY_PATH);
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X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicKey.getEncoded());
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KeyFactory keyFactory = KeyFactory.getInstance(RSA);
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publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
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Cipher cipher = Cipher.getInstance(RSANOPADDING);
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cipher.init(Cipher.ENCRYPT_MODE, publicKey);
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byte[] data = src.getBytes();
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int blockSize = 53;//根据异常提示设的53
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//根据块大小分块,不足一块的部分为一块
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int blocksNum = (int)Math.ceil((1.0*data.length)/blockSize);
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//加密
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for (int i = 0; i < blocksNum; i++) {
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if (i < blocksNum - 1) {
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cipher.doFinal(data, i * blockSize, blockSize);
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} else {
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cipher.doFinal(data, i * blockSize, data.length - i * blockSize);
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}
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}
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return data;
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}
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//私钥解密
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public String SRADecrypt(byte[] data) throws Exception{
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PrivateKey privateKey= (PrivateKey)readKey(path + PRIVATE_KEY_PATH);
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PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateKey.getEncoded());
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KeyFactory keyFactory = KeyFactory.getInstance(RSA);
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privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
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Cipher cipher = Cipher.getInstance(RSANOPADDING);
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cipher.init(Cipher.DECRYPT_MODE, privateKey);
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int blockSize = 64;//根据异常提示设的64
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//根据块大小分块,不足一块的部分为一块
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int blocksNum = (int)Math.ceil((1.0*data.length)/blockSize);
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//解密
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for (int i = 0; i < blocksNum; i++) {
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if (i < blocksNum - 1) {
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cipher.doFinal(data, i * blockSize, blockSize);
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} else {
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cipher.doFinal(data, i * blockSize, data.length - i * blockSize);
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}
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}
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return new String(data);
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}
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public void writeKey(String path, Key key) throws Exception {
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FileOutputStream fos = new FileOutputStream(path);
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ObjectOutputStream oos = new ObjectOutputStream(fos);
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oos.writeObject(key);
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oos.close();
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}
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public Key readKey(String path) throws Exception {
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FileInputStream fis = new FileInputStream(path);
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ObjectInputStream bis = new ObjectInputStream(fis);
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Object object = bis.readObject();
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bis.close();
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return (Key)object;
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}
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@Test
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public void testEncryptAndDecrypt() throws Exception {
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Cipher cipher = Cipher.getInstance(RSA);
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//读取公钥,进行加密
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PublicKey publicKey= (PublicKey) readKey("component/"+PUBLIC_KEY_PATH);
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cipher.init(Cipher.ENCRYPT_MODE, publicKey);
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//加密
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String sendInfo = "我的明文";
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byte[] results = cipher.doFinal(sendInfo.getBytes());
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//读取私钥,进行解密
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PrivateKey privateKey = (PrivateKey) readKey("component/"+PRIVATE_KEY_PATH);
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cipher.init(Cipher.DECRYPT_MODE, privateKey);
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//解密
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byte[] deciphered = cipher.doFinal(results);
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//得到明文
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String recvInfo = new String(deciphered);
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System.out.println(recvInfo);
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}
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@Test
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public void testSRA() throws Exception{
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PublicKey publicKey= (PublicKey)readKey("component/" + PUBLIC_KEY_PATH);
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X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicKey.getEncoded());
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KeyFactory keyFactory = KeyFactory.getInstance(RSA);
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publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
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Cipher cipher = Cipher.getInstance(RSA);
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cipher.init(Cipher.ENCRYPT_MODE, publicKey);
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byte[] result = cipher.doFinal("yuanyuan".getBytes());
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PrivateKey privateKey= (PrivateKey)readKey("component/" + PRIVATE_KEY_PATH);
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PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateKey.getEncoded());
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privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
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cipher = Cipher.getInstance(RSANOPADDING);
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cipher.init(Cipher.DECRYPT_MODE, privateKey);
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result = cipher.doFinal(result);
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System.out.println(new String(result));
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}
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}