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Java加解密工具类源码示例

目录
  • 一、对称加密算法 
  • 二、非对称加密算法
  • 三、散列算法
  • 四、加密算法的选择
  • 五、上源码
    • 5.1 AES对称加密
    • 5.2 RSA非对称加密
    • 5.3 MD5散列算法
  • 总结 

    一、对称加密算法 

    加密和解密使用相同密钥的加密算法。常用的算法包括DES、3DES、AES、DESX、Blowfish、RC4、RC5、RC6。

    DES(Data Encryption Standard):数据加密标准,速度较快,适用于加密大量数据的场合。

    3DES(Triple DES):是基于DES,对一块数据用三个不同的密钥进行三次加密,强度更高。

    AES(Advanced Encryption Standard):高级加密标准,速度快,安全级别高【128位秘钥】;

    二、非对称加密算法

    加密和解密使用不同密钥的加密算法,也称为公私钥加密。常见的算法包括RSA、DSA(数字签名用)、ECC(移动设备用)、Diffie-Hellman、El Gamal。

    • RSA:由 RSA 公司发明,是一个支持变长密钥的公共密钥算法,需要加密的文件块的长度也是可变的;【建议1024位秘钥】
    • DSA:数字签名算法,是一种标准的 DSS(数字签名标准)
    • ECC:椭圆曲线密码编码学【建议160位秘钥】。

    ECC VS RSA

    • 1)抗攻击性强。相同的密钥长度,其抗攻击性要强很多倍。
    • 2)计算量小,处理速度快。ECC总的速度比RSA、DSA要快得多。
    • 3)存储空间占用小。ECC的密钥尺寸和系统参数与RSA、DSA相比要小得多,意味着它所占的存贮空间要小得多。这对于加密算法在IC卡上的应用具有特别重要的意义。
    • 4)带宽要求低。当对长消息进行加解密时,三类密码系统有相同的带宽要求,但应用于短消息时ECC带宽要求却低得多。带宽要求低使ECC在无线网络领域具有广泛的应用前景。

    三、散列算法

    除法散列法 平方散列法 斐波那契(Fibonacci)散列法 随机数法

    单向散列js函数一般用于产生消息摘要,密钥加密等,常用的算法包括MD2、MD4、MD5、HAVAL、SHA、SHA-1、HMAC、HMAC-MD5、HMAC-SHA1。

    • MD5(Message Digest Algorithm 5):是RSA数据安全公司开发的一种单向散列算法,非可逆,相同的明文产生相同的密文。
    • SHA(Secure Hash Algorithm):可以对任意长度的数据运算生成一个160位的数值;

    SHA-1 VS MD5 [二者均由MD4导出]

    • 1)SHA-1摘要比MD5摘要长32位。使用强行技术,产生任何一个报文使其摘要等于给定报摘要的难度对MD5是2^(128)数量级的操作,而对SHA-1则是2^(160)数量级的操作。这样,SHA-1对强行攻击有更大的强度。
    • 2)MD5易受密码分析的攻击,SHA-1显得不易受这样的攻击。
    • 3)在相同的硬件上,SHA-1的运行速度比MD5慢。

    四、加密算法的选择

    1.单方密码存储建议直接使用散列算法(MD5即可,配合密码更新策略)。

    2.内部信息加密传输建议使用对称加密效率跟高(AES)。

    3.外部数据传输建议使用非对称加密,秘钥保存更安全(RSA)。

    4.HTTPS高级用法:采用非对称加密算法管理对称算法的密钥,然后用对称加密算法加密数据,这样我们就集成了两类加密算法的优点,既实现了加密速度快的优点,又实现了安全方便管理密钥的优点。

    五、上源码

    5.1 AES对称加密

    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.codec.binary.Base64;
    import org.apache.commons.lang3.ArrayUtils;
    import org.springframework.util.StringUtils;
    
    import Javax.crypto.Cipher;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    import java.nio.charset.StandardCharsets;
    
    /**
     * <p>
     * AES加密工具
     * </p>
     *
     * @author ocean
     * @version 1.0.0
     * @date 2023/5/4 14:51
     */
    @Slf4j
    public class AESUtils {
    
        // 秘钥 16
        private static final String SECRET_KEY = "1111111111111111";
        // 秘钥 24
        //private static final String SECRET_KEY = "111111111111111122222222";
        // 秘钥 32
        //private static final String SECRET_KEY = "11111111111111112222222233333333";
    
        // 算法
        private static final String ALGORITHM = "AES";
    
        private static final String UTF8 = StandardCharsets.UTF_8.name();
    
        /**
         * 字符串加密
         *
         * @param message   明文字符串
         * @param secretKey 秘钥
         * @return 加密字符串
         */
        public static String encryption(String message, String secretKey) {
            if (!StringUtils.hasLength(message)) {
                log.error("encryption message should not be null or empty.");
            }
            byte[] encodeBytes = encryption(message.getBytes(StandardCharsets.UTF_8), secretKey);
            return Base64.encodeBase64String(encodeBytes);
        }
    
        /**
         * 字符串加密
         *
         * @param messageBytes 明文字节数组
         * @param secretKey    秘钥
         * @return 加密字节数组
         */
        public static byte[] encryption(byte[] messageBytes, String secretKey) {
            if (ArrayUtils.isEmpty(messageBytes)) {
                log.error("encryption message should not be empty.");
            }
            if (!StringUtils.hasLength(secretKey)) {
                log.error("secretKey {}, encryption key should not be null or empty.", secretKey);
            }
            Cipher cipher = getCipher(secretKey, Cipher.ENCRYPT_MODE);
            byte[] encryptionBytes = null;
            try {
                encryptionBytes = cipher.doFinal(messageBytes);
            } catch (Exception e) {
                log.error("encryption fail. ", e);
            }
            return encryptionBytes;
        }
    
        /**
         * 字符串加密
         *
         * @param encryptionMessage 加密字符串
         * @param secretKey         秘钥
         * @return 明文字符串
         */
        public static String decrypt(String encryptionMessage, String secretKey) {
            if (!StringUtils.hasLength(encryptionMessage)) {
                log.error("decrypt encryptionMessage should not be null or empty.");
            }
            byte[] decodeBytes = decrypt(Base64.decodeBase64(encryptionMessage.getBytes(StandardCharsets.UTF_8)), secretKey);
            http://www.devze.comreturn new String(decodeBytes, StandardCharsets.UTF_8);
        }
    
    
        /**
         * 字符串加密
         *
         * @param encryptedBytes 加密字节数组
         * @param secretKey      秘钥
         * @return 明文字节数组
         */
        public static byte[] decrypt(byte[] encryptedBytes, String secretKey) {
            if (ArrayUtils.isEmpty(encryptedBytes)) {
                log.error("decrypt encryptedBytes should not be empty.");
            }
            if (!StringUtils.hasLength(secretKey)) {
                log.error("secretKey {}, decrypt key should not be null or empty.", secretKey);
            }
            Cipher cipher = getCipher(secretKey, Cipher.DECRYPT_MODE);
            byte[] decodeBytes = null;
            try {
                decodeBytes = cipher.doFinal(encryptedBytes);
            } catch (Exception e) {
                log.error("decrypt fail. ", e);
            }
            return decodeBytes;
        }
    
        private static Cipher getCipher(String key, int mode) {
            Cipher cipher = null;
            SecretKey secretKey;
            try {
                cipher = Cipher.getInstance(ALGORITHM);
                byte[] keyBytes = key.getBytes(UTF8);
                secretKey = new SecretKeySpec(keyBytes, ALGORITHM);
                cipher.init(mode, secretKey);
            } catch (Exception e) {
                log.error("getAESCipher fail. ", e);
            }
            return cipher;
        }
    
        public static void main(String[] args) {
            String data = "ocean测试!@#";
            log.info("AES秘钥长度只能为16、24、32:{}", SECRET_KEY.getBytes(StandardCharsets.UTF_8).length);
            String encryptionData = encryption(data, SECRET_KEY);
            log.info("加密后:{}", encryptionData);
            String decryptData = decrypt(encryptionData, SECRET_KEY);
            log.info("解密后:{}", decryptData);
        }
    
    
    }
    

    5.2 RSA非对称加密

    PSCK#8 - PSCK#1
    <!-- https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk15on -->
    <dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.52</version>
    </dependency>
    import java.io.StringWriter;
    import java.security.KeyFactory;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.NoSuchAlgorithmException;
    import java.security.PrivateKey;
    import java.security.PublicKey;
    imporwww.devze.comt java.security.Signature;
    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 java.util.HashMap;
    import java.util.Map;
    
    import javax.crypto.Cipher;
    
    import org.apache.commons.codec.binary.Base64;
    import org.bouncycastle.asn1.ASN1Encodable;
    import org.bouncycastle.asn1.ASN1Primitive;
    import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
    import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
    import org.bouncycastle.util.io.pem.PemObject;
    import org.bouncycastle.util.io.pem.PemWriter;
    
    import sun.misc.BASE64Decoder;
    import sun.misc.BASE64Encoder;
    
    public class RsaUtils {
    
    	public static final int KEY_SIZE = 2048;
    	public static final String ALGORITHM = "RSA";
    
    
    	public static final String PUBLIC_KEY = "xxxxpublicKeyxxxx";
    	public static final String PRIVATE_KEY = "xxxxprivateKeyxxxx";
    
    	public static final String CLEAR_TEXT_STRING = "明文字符串";
    
    	public static BASE64Encoder encoder = new BASE64Encoder();
    	public static BASE64Decoder decoder = new BASE64Decoder();
    
    	public static void main(String[] args) throws Exception {
    		// PSCK#8
    		Map<String, String> keyMap = RsaUtil.generateKeyBytes();
    		System.out.println("PSCK#8-PRIVATEKEY:"+ keyMap.get(RsaUtil.PRIVATE_KEY));
    		System.out.println("PSCK#8-PUBLICKEY:" + keyMap.get(RsaUtil.PUBLIC_KEY));
    		
    		PublicKey publicKey8 = RsaUtil.restorePublicKey(keyMap.get(RsaUtil.PUBLIC_KEY));
    		PrivateKey privateKey8 = RsaUtil.restorePrivateKey(keyMap.get(RsaUtil.PRIVATE_KEY));
    
    		
    		// ============公钥加密-私钥解密============
    		Cipher cipher = Cipher.getInstance(ALGORITHM);
    		cipher.init(Cipher.ENCRYPT_MODE, publicKey8);
    		String messageEn = Base64.encodeBase64String(cipher.doFinal(CLEAR_TEXT_STRING.getBytes("UTF-8")));
    		System.out.println(CLEAR_TEXT_STRING + "\t加密后的字符串为:" + messageEn);
    		cipher.init(Cipher.DECRYPT_MODE, privateKey8);
    		String messageDe = new String(cipher.doFinal(Base64.decodeBase64(messageEn.getBytes("UTF-8"))));
    		System.out.println("还原后的字符串为:" + messageDe);
    	http://www.devze.com	// ============公钥加密-私钥解密============
    
    	
    
    		// ============PSCK#8>PSCK#1============
    		byte[] privbytes = privateKey8.getEncoded();
    		PrivateKeyInfo pkInfo = PrivateKeyInfo.getInstance(privBytes);
    		ASN1Encodable encodable = pkInfo.getPrivateKey();
    		ASN1Primitive primitive = encodable.toASN1Primitive();
    
    		byte[] privateKeyPKCS1 = primitive.getEncoded();
    		PemObject pemObject = new PemObject("RSA PRIVATE KEY", privateKeyPKCS1);
    		StringWriter stringWriter = new StringWriter();
    		PemWriter pemWriter = new PemWriter(stringWriter);
    		pemWriter.writeObject(pemObject);
    		pemWriter.close();
    		String pemString = stringWriter.toString();
    		System.out.println("PSCK#1-PRIVATEKEY:" + pemString);
    
    		byte[] pubBytes = publicKey8.getEncoded();
    		SubjectPublicKeyInandroidfo spkInfo = SubjectPublicKeyInfo
    				.getInstance(pubBytes);
    		ASN1Primitive punlic = spkInfo.parsePublicKey();
    		byte[] publicKeyPKCS1 = punlic.getEncoded();
    
    		PemObject punlicpemObject = new PemObject("RSA PUBLIC KEY",
    				publicKeyPKCS1);
    		StringWriter punlicstringWriter = new StringWriter();
    		PemWriter punlicpemWriter = new PemWriter(punlicstringWriter);
    		punlicpemWriter.writeObject(punlicpemObject);
    		punlicpemWriter.close();
    		String publicemString = punlicstringWriter.toString();
    		System.out.println("PSCK#8-PUBLICKEY:" + publicemString);
    		// ============PSCK#8>PSCK#1============
    
    		// ============私钥签名公钥验签============
    		// PSCK#8-PRIVATEKEY 私钥签名
    		Signature signature = Signature.getInstance("SHA256WithRSA");
    		signature.initSign(privateKey8);
    		signature.update(CLEAR_TEXT_STRING.getBytes());
    		byte[] signed = signature.sign();
    		String sign = encoder.encode(signed);
    
    		// PSCK#8-PUBLICKEY 公钥验签
    		signature.initVerify(publicKey8);
    		signature.update(CLEAR_TEXT_STRING.getBytes());
    		boolean verify = signature.verify(decoder.decodeBuffer(sign));
    
    		System.out.println("CLEAR_TEXT_STRING:" + CLEAR_TEXT_STRING);
    		System.out.println("SIGN:" + sign.replaceAll("\r|\n", ""));
    		System.out.println(verify);
    		// ============私钥签名公钥验签============
    	}
    
    	/**
    	 * 公私钥生成
    	 * 
    	 * @return
    	 */
    	public static Map<String, String> generateKeyBytes() {
    		try {
    			KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
    			keyPairGenerator.initialize(KEY_SIZE);
    			KeyPair keyPair = keyPairGenerator.generateKeyPair();
    
    			RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
    			RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
    
    			Map<String, String> keyMap = new HashMap<String, String>();
    			keyMap.put(PUBLIC_KEY, new String(Base64.encodeBase64(publicKey.getEncoded())));
    			keyMap.put(PRIVATE_KEY, new String(Base64.encodeBase64(privateKey.getEncoded())));
    			return keyMap;
    		} catch (NoSuchAlgorithmException e) {
    			e.printStackTrace();
    		}
    		return null;
    	}
    	/**
    	 * 公钥生成
    	 * @param key
    	 * @return
    	 */
    	public static PublicKey restorePublicKey(String key) {
    		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(Base64.decodeBase64(key));
    		try {
    			KeyFactory factory = KeyFactory.getInstance(ALGORITHM);
    			PublicKey publicKey = factory.generatePublic(x509EncodedKeySpec);
    			return publicKey;
    		} catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
    			e.printStackTrace();
    		}
    		return null;
    	}
    	
    	/**
    	 * 私钥生成
    	 * @param key
    	 * @return
    	 */
        public static PrivateKey restorePrivateKey(String key) {
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(key));
            try {
                KeyFactory factory = KeyFactory.getInstance(ALGORITHM);
                PrivateKey privateKey = factory
                        .generatePrivate(pkcs8EncodedKeySpec);
                return privateKey;
            } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
                e.printStackTrace();
            }
            return null;
        }
    
    }
    

    5.3 MD5散列算法

    import lombok.extern.slf4j.Slf4j;
    
    import java.security.MessageDigest;
    
    @Slf4j
    public class MD5Util {
        public static final int SIZE_FACTOR = 2;
        private static final String[] hexDigits = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
    
        public static String MD5Encode(String origin, String charsetname) {
            String resultString = null;
            try {
                resultString = origin;
                MessageDigest md = MessageDigest.getInstance("MD5");
                if (charsetname == null || "".equals(charsetname)) {
                    resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
                } else {
                    resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
                }
            } catch (Exception exception) {
                log.error("MD5Util MD5Encode error", exception);
            }
            return resultString;
        }
    
        private static String byteArrayToHexString(byte[] b) {
            StringBuffer resultSb = new StringBuffer();
            for (int i = 0; i < b.length; i++) {
                resultSb.append(byteToHexString(b[i]));
            }
            return resultSb.toString();
        }
    
        private static String byteToHexString(byte b) {
            int n = b;
            if (n < 0) {
                n += 256;
            }
            int d1 = n / 16;
            int d2 = n % 16;
            return hexDigits[d1] + hexDigits[d2];
        }
    
        public static String encode(String str) {
            try {
                byte[] hash = MessageDigest.getInstance("MD5").digest(str.getBytes("utf-8"));
                StringBuilder hex = new StringBuilder(hash.length * SIZE_FACTOR);
                for (byte b : hash) {
                    hex.append(String.format("%02x", b));
                }
                return hex.toString();
            } catch (Exception e) {
                log.error("MD5 encode error for {}, error is {}", str, e.getMessage(), e);
            }
            return null;
        }
    }

    总结 

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