Java加密算法

Java加密算法

import org.apache.commons.lang3.ArrayUtils;
import org.apache.tomcat.util.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * AES对称加密
 * RSA非对称加密
 * Hex加密
 * 私钥签名，公钥验证
*/
public class CryptTest {

    private static final String UTF8 = "UTF-8";

    public static void main(String[] args) throws Exception {
        String data = "hello";

        /**
         * AES对称加密
         */
        String key = "$i%2i9343kl3#df5"; //AES 16位的密钥
        String aesEncoded = AesUtils.AESEncrypt(key, data);
        String aesDecoded = AesUtils.AESDecrypt(key, aesEncoded);
        System.out.println("\naesEncoded: " + aesEncoded + "\naesDecoded: " + aesDecoded);

        /**
         * RSA非对称加密
         */
        Map<String, String> keys = RSAUtils.generateKey("appKey");
        String publicKey = keys.get("publicKey");
        String privateKey = keys.get("privateKey");

        String rsaEncoded = RSAUtils.publicEncrypt(publicKey, data);
        String rsaDecoded = RSAUtils.privateDecrypt(privateKey, rsaEncoded);
        System.out.println("\nrsaEncoded: " + rsaEncoded + "\nrsaDecoded: " + rsaDecoded);

        String rsaEncodedBySegment = RSAUtils.publicEncryptBySegment(publicKey, data);
        String rsaDecodedBySegment = RSAUtils.privateDecryptBySegment(privateKey, rsaEncodedBySegment);
        System.out.println("\nrsaEncodedBySegment: " + rsaEncodedBySegment + "\nrsaDecodedBySegment: " + rsaDecodedBySegment);

        /**
         * Hex加密
         */
        String hexEncoded = HexUtils.byte2hex(data.getBytes(UTF8));
        String hexDecoded = new String(HexUtils.hex2byte(hexEncoded), UTF8);
        System.out.println("\nhexEncoded: " + hexEncoded + "\nhexDecoded: " + hexDecoded);

        /**
         * 数字签名
         */
        String signature = SignUtils.sign(data, privateKey);
        boolean result = SignUtils.verify(data, signature, publicKey);
        System.out.println("\nsignature: " + signature + "\nresult: " + result);
    }

}

/**
 * AES对称加密
 */
class AesUtils {

    private static Logger log = LoggerFactory.getLogger(AesUtils.class);

    private static final String AESTYPE = "AES/ECB/PKCS5Padding";


    public static String AESEncrypt(String keyStr, String plainText) {
        byte[] encrypt = null;
        try {
            SecretKeySpec keySpec = new SecretKeySpec(keyStr.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance(AESTYPE);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec);
            encrypt = cipher.doFinal(plainText.getBytes());
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }
        return new String(Base64.encodeBase64(encrypt));
    }

    public static String AESDecrypt(String keyStr, String encryptData) {
        byte[] decrypt = null;
        try {
            SecretKeySpec key = new SecretKeySpec(keyStr.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance(AESTYPE);
            cipher.init(Cipher.DECRYPT_MODE, key);
            decrypt = cipher.doFinal(Base64.decodeBase64(encryptData));
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }
        return new String(decrypt);
    }
}

/**
 * RSA加密明文最大长度117字节，解密要求密文最大长度为128字节，所以在加密和解密的过程中需要分块进行。
 *  由于非对称加密速度极其缓慢，一般数据量较大时不使用它来加密而是使用对称加密，非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 */
class RSAUtils {

    // 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，分段时不是最大会报错 Caused by: javax.crypto.IllegalBlockSizeException: Data must not be longer than 117 bytes
    private static final int MAX_DECRYPT_BLOCK = 128;

    private static final String UTF8 = "UTF-8";

    private static final String RSA_ALGORITHM = "RSA";

    private static Logger log = LoggerFactory.getLogger(AesUtils.class);

    public static String publicEncrypt(String strPublicKey, String content) throws IOException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeySpecException {
        byte[] keyBytes = base64Decode(strPublicKey);
        byte[] encryptData = publicEncrypt(getPublicKey(keyBytes), content.getBytes(UTF8));
        return base64Encode(encryptData);
    }

    public static byte[] publicEncrypt(PublicKey publicKey, byte[] content) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        if (publicKey == null) {
            throw new IllegalArgumentException("加密公钥为空");
        }
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(content);
    }

    public static String privateDecrypt(String strPrivateKey, String encryptData) throws IOException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeySpecException {
        byte[] keyBytes = base64Decode(strPrivateKey);
        byte[] content = privateDecrypt(getPrivateKey(keyBytes), base64Decode(encryptData));
        return new String(content, UTF8);
    }

    public static byte[] privateDecrypt(PrivateKey privateKey, byte[] encryptData) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        if (privateKey == null) {
            throw new IllegalArgumentException("解密私钥为空");
        }
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        return cipher.doFinal(encryptData);
    }

    // 生成appkey对应的公钥，私钥
    public static Map generateKey(String appKey) {
        try {
            KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
            kpg.initialize(1024);
            KeyPair keyPair = kpg.genKeyPair();
            String publicKey = base64Encode(keyPair.getPublic().getEncoded());
            String privateKey = base64Encode(keyPair.getPrivate().getEncoded());
            Map map = new HashMap();
            map.put("publicKey", publicKey);
            map.put("privateKey",privateKey);
            System.out.println(map);
            return map;
        } catch (Exception e) {
            log.error(appKey+"生成加密异常！");
        }
        return null;
    }

    public static PublicKey getPublicKey(byte[] keyBytes) throws InvalidKeySpecException, NoSuchAlgorithmException {
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        return keyFactory.generatePublic(keySpec);
    }

    public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException, InvalidKeySpecException {
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        return keyFactory.generatePrivate(keySpec);
    }

    private static String base64Encode(byte[] data) {
        if (data == null)
            return "";
        return Base64.encodeBase64String(data);
    }

    private static byte[] base64Decode(String base64String) throws IOException {
        if (base64String == null)
            return new byte[]{};
        return Base64.decodeBase64(base64String);
    }

    // 公钥加密，加密参数过长，采用分段方式
    public static String publicEncryptBySegment(String strPublicKey, String content) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, IOException, InvalidKeySpecException {
        byte[] keyBytes = base64Decode(strPublicKey);
        PublicKey publicKey = getPublicKey(keyBytes);
        if (publicKey == null) {
            throw new IllegalArgumentException("加密公钥为空");
        }
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return base64Encode(doFinalBySegment(cipher, content.getBytes(UTF8), MAX_ENCRYPT_BLOCK));
    }

    // 私钥解密，解密参数过长，采用分段方式
    public static String privateDecryptBySegment(String strPrivateKey, String content) throws NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeySpecException, IOException, InvalidKeyException {
        byte[] keyBytes = base64Decode(strPrivateKey);
        PrivateKey privateKey = getPrivateKey(keyBytes);
        if (privateKey == null) {
            throw new IllegalArgumentException("解密私钥为空");
        }
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        return new String(doFinalBySegment(cipher, base64Decode(content), MAX_DECRYPT_BLOCK), UTF8);
    }

    public static byte[] doFinalBySegment(Cipher cipher, byte[] data, int segmentSize) throws BadPaddingException, IllegalBlockSizeException, IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        for (int i = 0; i < data.length; i += segmentSize) {
            byte[] result = cipher.doFinal(ArrayUtils.subarray(data, i,i + segmentSize));
            out.write(result);
        }
        return out.toByteArray();
    }
}
/**
 * 数字摘要：采用单项Hash函数将需要加密的明文“摘要”成一串固定长度（128位）的密文，又称数字指纹
 * 数字签名：对传送数据生成摘要并使用私钥进行加密，遵循私钥签名，公钥验证的方式
 * 1.为了保证http请求数据的安全性和防篡改性。我们通常要对请求参数进行一些加密。
 *   http请求参数:
 *   (1)appkey：合作方平台标识，接口协议中通常会提供一个appKey作为唯一的标识。
 *   (2)appSecret：作为接入密钥。
 *   (3)time：Unix时间戳（10位）
 * 2.对请求参数生成签名
 *   sign = md5(待签名字符串)
 *   待签名字符串为: 将参数按参数名排序，拼接成键值对，如appKey=test_id&appSecret=A272ADAA3637&time=1423212323&username=lily
 * 3.将明文参数和签名一起发送给对方
 *   appKey=test_id&appSecret=A272ADAA3637&time=1423212323&username=lily&sign=签名串
 */
class SignUtils {

    private static final String MD5_ALGORITHM = "MD5";
    private static final String SIGNATURE_ALGORITHM = "SHA1WithRSA";
    private static final String UTF8 = "UTF-8";

    public static String sign(String data, String privateKey) throws UnsupportedEncodingException, NoSuchAlgorithmException, SignatureException, InvalidKeySpecException, InvalidKeyException {
        byte[] content = data.getBytes(UTF8);
        // 先做摘要
        MessageDigest md = MessageDigest.getInstance(MD5_ALGORITHM);
        md.update(content);
        byte[] digest = md.digest();
        // 进行签名
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(RSAUtils.getPrivateKey(Base64.decodeBase64(privateKey.getBytes())));
        signature.update(digest);
        byte[] signByte = signature.sign();
        String signText = Base64.encodeBase64String(signByte);
        System.out.println(signText);
        return signText;
    }

    public static boolean verify(String data, String signText, String publicKey) throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeySpecException, InvalidKeyException, SignatureException {
        byte[] content = data.getBytes(UTF8);
        // 先做摘要
        MessageDigest md = MessageDigest.getInstance(MD5_ALGORITHM);
        md.update(content);
        byte[] digest = md.digest();
        // 进行验签
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(RSAUtils.getPublicKey(Base64.decodeBase64(publicKey.getBytes())));
        signature.update(digest);
        boolean result = signature.verify(Base64.decodeBase64(signText));
        return result;
    }
}

/**
 * Hex加密，hex十六进制和acsii码之间的转换，可用在url参数解决特殊字符的问题，将加密数据再加密成16进制
 */
class HexUtils {
    private static final int INT_VALUE_2 = 2;
    private static char[] c = "0123456789ABCDEF".toCharArray();

    public static String byte2hex(byte[] b) {
        if (b == null) {
            return null;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < b.length; i++) {
            int v = b[i] & 0xff;
            sb.append(c[v / 0x10]).append(c[v % 0x10]);
        }
        return sb.toString();
    }

    public static byte[] hex2byte(String s) {
        if (s == null) {
            return null;
        }
        byte[] b = s.getBytes();
        if ((b.length % INT_VALUE_2) != 0) {
            throw new IllegalArgumentException();
        }
        byte[] b2 = new byte[b.length / INT_VALUE_2];
        for (int n = 0; n < b.length; n += INT_VALUE_2) {
            String item = new String(b, n, INT_VALUE_2);
            b2[n / INT_VALUE_2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }
}