JDK中带有部分加密算法的实现类,主要的是java.security和javax.crypto包下的类,还可以使用Bouncy Castle(丰富JDK中加密算法的不足)jar包是:bcprov-jdk15on-1.57.jar和Commons Codec(简化JDK中加密的操作)jar包是:commons-codec-1.10.jar
Base64用于网络中传输的数据进行编码,严格意义上属于编码的格式,有64个字符的对应的编码,Base64就是将内容按照该格式进行编码。可以对数据编码和解码,是可逆的,安全度较低,不过,也可以作为最基础最简单的加密算法用于加密要求较弱的情况
Base64可以使用JDk中自带的类实现,还可以使用Bouncy Castle(简称bc)或Commons Codec(简称cc)实现
加密数据:
private static String src="Hello Base64";
导入的类:
import java.io.IOException;
import org.apache.commons.codec.binary.Base64;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
JDk实现主要使用用BASE64Encoder和BASE64Decoder类的方法(注意:在Eclipse中使用JDK的Base64可能会出现找不到的问题,是因为Base64Encoder并不属于JDK标准库范畴,但是又包含在了JDK中,需要我们手动导入\jre\lib目录下的rt.jar包即可):
public static void jdkBase64(){
try {
BASE64Encoder encoder=new BASE64Encoder();
String encode = encoder.encode(src.getBytes());
System.out.println("encode: "+encode);
BASE64Decoder decoder=new BASE64Decoder();
String decode=new String(decoder.decodeBuffer(encode));
System.out.println("decode: "+decode);
} catch (IOException e) {
e.printStackTrace();
}
}
bc实现主要是用Base64类的方法:
public static void bouncybastleBase64(){
byte[] encode = org.bouncycastle.util.encoders.Base64.encode(src.getBytes());
System.out.println("encode: "+new String(encode));
byte[] decode = org.bouncycastle.util.encoders.Base64.decode(encode);
System.out.println("decode: "+new String(decode));
}
cc实现也是用Base64类,不过与bc的是不一样的,不同包中的类,只是名字一样:
public static void commonscodecBase64(){
byte[] encode=Base64.encodeBase64(src.getBytes());
System.out.println("encode: "+new String(encode)); //需要转化为String
byte[] decode = Base64.decodeBase64(encode);
System.out.println("decode: "+new String(decode));
}
摘要算法主要分为MD,SHA和Hmac算法,摘要算法其实是用于效验数据完整性的,我们在下载某些文件时,会有MD5和SHA1值提供我们效验下载的文件是否完整,可以用于根据数据生成其唯一的摘要值,无法根据摘要值知道原数据,属于不可逆的
加密数据:
private static String src="Hello MD";
导入的类:
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import java.security.Security;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.MD2Digest;
import org.bouncycastle.crypto.digests.MD4Digest;
import org.bouncycastle.crypto.digests.MD5Digest;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
JDK有MD2和MD5的实现,使用的是MessageDigest类,而没有MD4的实现:
public static void jdkMD5(){
try {
MessageDigest md=MessageDigest.getInstance("MD5");
byte[] digest = md.digest(src.getBytes());
System.out.println("JDK MD5: "+Hex.encodeHexString(digest)); //使用的是cc中带的Hex需要转换为十六进制
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
public static void jdkMD2(){
try {
MessageDigest md=MessageDigest.getInstance("MD2");
byte[] digest = md.digest(src.getBytes());
System.out.println("JDK MD2: "+Hex.encodeHexString(digest));
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
而bc这三种都有,使用的是Digest 类:
public static void bcMD4(){
//方式一
// Digest digest=new MD4Digest();
// digest.update(src.getBytes(), 0, src.getBytes().length);
// byte[] md4Bytes=new byte[digest.getDigestSize()];
// digest.doFinal(md4Bytes, 0);
// System.out.println("BC MD4: "+org.bouncycastle.util.encoders.Hex.toHexString(md4Bytes));
//方式二(通过添加provider的方式,将sun的改为bc的provider)
try {
Security.addProvider(new BouncyCastleProvider()); //通过添加provider的方式
MessageDigest md=MessageDigest.getInstance("MD4");
byte[] digest = md.digest(src.getBytes());
System.out.println("BC MD4: "+Hex.encodeHexString(digest));
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
public static void bcMD5(){
Digest digest=new MD5Digest();
digest.update(src.getBytes(), 0, src.getBytes().length);
byte[] md4Bytes=new byte[digest.getDigestSize()];
digest.doFinal(md4Bytes, 0);
System.out.println("BC MD5: "+org.bouncycastle.util.encoders.Hex.toHexString(md4Bytes));
}
public static void bcMD2(){
Digest digest=new MD2Digest();
digest.update(src.getBytes(), 0, src.getBytes().length);
byte[] md4Bytes=new byte[digest.getDigestSize()];
digest.doFinal(md4Bytes, 0);
System.out.println("BC MD2: "+org.bouncycastle.util.encoders.Hex.toHexString(md4Bytes));
}
cc和JDK是一样的,毕竟是对JDK加密的简化,直接使用DigestUtils中的方法,很简单,而且前两种方法还需要将MD值转换为十六进制,cc直接就帮我们转了:
public static void ccMD2(){ //有方法直接就可以转换十六进制
System.out.println("CC MD2: "+DigestUtils.md2Hex(src.getBytes()));
}
public static void ccMd5(){
System.out.println("CC MD5: "+DigestUtils.md5Hex(src.getBytes()));
}
加密数据:
private static String src="Hello SHA";
要导入的类:
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SHA1Digest;import sun.security.provider.SHA;
JDK实现方式(同样是使用MessageDigest):
public static void jdkSHA1(){
MessageDigest digest;
try {
digest = MessageDigest.getInstance("SHA");
digest.update(src.getBytes());
System.out.println("JDK SHA1: "+Hex.encodeHexString(digest.digest()));
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
bc的实现方式(同样是Digest 类):
public static void mcSHA1(){
Digest digest=new SHA1Digest();
digest.update(src.getBytes(),0,src.getBytes().length);
byte[] sha1Byte1=new byte[digest.getDigestSize()];
digest.doFinal(sha1Byte1, 0);
System.out.println("MC SHA1:"+org.bouncycastle.util.encoders.Hex.toHexString(sha1Byte1));
}
cc的实现方式:
public static void ccsha(){
System.out.println("CC sha1:"+DigestUtils.sha1Hex(src));
}
private static String src="Hello HMAC";
要导入的类:
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.crypto.digests.MD5Digest;
import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.crypto.params.KeyParameter;
JDK的实现方式:
public static void jdkHmacMD5(){
try {
KeyGenerator keyGenerator=KeyGenerator.getInstance("HmacMD5"); //初始化KeyGenerator
SecretKey secretKey=keyGenerator.generateKey(); //产生密钥
//byte[] key=secretKey.getEncoded(); //获得密钥(默认生成)
byte[] key=Hex.decodeHex(new char[]{'a','a','a','a','a','a','a','a','a','a'}); //手动生成密钥(十位)
SecretKey secretKey2=new SecretKeySpec(key, "HmacMD5"); //还原密钥
Mac mac=Mac.getInstance(secretKey2.getAlgorithm()); //实例化mac
//初始化mac
mac.init(secretKey2);
byte[] hmacMD5Bytes=mac.doFinal(src.getBytes());
System.out.println("jdk hmacMD5: "+Hex.encodeHexString(hmacMD5Bytes));
} catch (Exception e) {
e.printStackTrace();
}
}
bc的实现方式:
public static void bcHmacMd5(){
HMac hMac=new HMac(new MD5Digest());
hMac.init(new KeyParameter(org.bouncycastle.util.encoders.Hex.decode("aaaaaaaaaa"))); //需要十位密钥
hMac.update(src.getBytes(),0,src.getBytes().length);
byte[] hmacMD5=new byte[hMac.getMacSize()];
hMac.doFinal(hmacMD5, 0);
System.out.println("bc hmacMD5: "+org.bouncycastle.util.encoders.Hex.toHexString(hmacMD5));
}
严格意义上的加密算法,分为对称和非对称加密算法,所谓对称是说发送方和接收方的密钥是一样的,而非对称我们后面再说。因为密钥一样所以安全性跟非对称比较来说就不太安全了
对称加密算法主要分为:DES , 3DES(3重DES) , AES(想要替代DES) , PBE(基于口令的对称算法)
private static String src="Hello DES";
导入的类:
import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
JDK的实现方式:
public static void jdkDES(){
try {
//生成key
KeyGenerator keyGenerator=KeyGenerator.getInstance("DES");
keyGenerator.init(56); //指定key长度,同时也是密钥长度(56位)
SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
byte[] key = secretKey.getEncoded(); //生成key
//key转换成密钥
DESKeySpec desKeySpec=new DESKeySpec(key);
SecretKeyFactory factory=SecretKeyFactory.getInstance("DES");
SecretKey key2 = factory.generateSecret(desKeySpec); //转换后的密钥
//加密
Cipher cipher=Cipher.getInstance("DES/ECB/PKCS5Padding"); //算法类型/工作方式/填充方式
cipher.init(Cipher.ENCRYPT_MODE, key2); //指定为加密模式
byte[] result=cipher.doFinal(src.getBytes());
System.out.println("jdkDES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE,key2); //相同密钥,指定为解密模式
result = cipher.doFinal(result); //根据加密内容解密
System.out.println("jdkDES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
bc的实现方式,为了和JDK的实现方式一致(不想记太多类),采用了添加provider的方式 :
public static void bcDES(){
try {
//通过改变provider的方式
Security.addProvider(new BouncyCastleProvider());
//生成key,使用bc需要在后面指定"BC"
KeyGenerator keyGenerator=KeyGenerator.getInstance("DES","BC");
keyGenerator.getProvider();
keyGenerator.init(56); //指定key长度,同时也是密钥长度
SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
byte[] key = secretKey.getEncoded(); //生成key
//key转换成密钥
DESKeySpec desKeySpec=new DESKeySpec(key);
SecretKeyFactory factory=SecretKeyFactory.getInstance("DES");
SecretKey key2 = factory.generateSecret(desKeySpec); //转换后的密钥
//加密
Cipher cipher=Cipher.getInstance("DES/ECB/PKCS5Padding"); //算法类型/工作方式/填充方式
cipher.init(Cipher.ENCRYPT_MODE, key2);
byte[] result=cipher.doFinal(src.getBytes());
System.out.println("bcDES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE,key2); //相同密钥
result = cipher.doFinal(result); //根据加密内容解密
System.out.println("bcDES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
就是记得添加bc的provider,和KeyGenerator.getInstance的参数(“DES”,“BC”)
private static String src="Hello 3DES";
导入的类:
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
JDK的实现方法:
public static void jdkDES(){
try {
//生成key
KeyGenerator keyGenerator=KeyGenerator.getInstance("DESede");
//keyGenerator.init(112); //3DES需要112 or 168位
keyGenerator.init(new SecureRandom()); //或者使用这种方式默认长度,无需指定长度
SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
byte[] key = secretKey.getEncoded(); //生成key
//key转换成密钥
DESedeKeySpec desKeySpec=new DESedeKeySpec(key);
SecretKeyFactory factory=SecretKeyFactory.getInstance("DESede");
SecretKey key2 = factory.generateSecret(desKeySpec); //转换后的密钥
//加密
Cipher cipher=Cipher.getInstance("DESede/ECB/PKCS5Padding"); //算法类型/工作方式/填充方式
cipher.init(Cipher.ENCRYPT_MODE, key2); //指定为加密模式
byte[] result=cipher.doFinal(src.getBytes());
System.out.println("jdk3DES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE,key2); //相同密钥,指定为解密模式
result = cipher.doFinal(result); //根据加密内容解密
System.out.println("jdk3DES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
bc的实现方式:
public static void bcDES(){
try {
//通过改变provider的方式,其他操作一样
Security.addProvider(new BouncyCastleProvider());
//生成key
KeyGenerator keyGenerator=KeyGenerator.getInstance("DESede");
keyGenerator.init(new SecureRandom());
SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
byte[] key = secretKey.getEncoded(); //生成key
//key转换成密钥
DESedeKeySpec desKeySpec=new DESedeKeySpec(key);
SecretKeyFactory factory=SecretKeyFactory.getInstance("DESede");
SecretKey key2 = factory.generateSecret(desKeySpec); //转换后的密钥
//加密
Cipher cipher=Cipher.getInstance("DESede/ECB/PKCS5Padding"); //算法类型/工作方式/填充方式
cipher.init(Cipher.ENCRYPT_MODE, key2); //指定为加密模式
byte[] result=cipher.doFinal(src.getBytes());
System.out.println("jdk3DES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE,key2); //相同密钥,指定为解密模式
result = cipher.doFinal(result); //根据加密内容解密
System.out.println("jdk3DES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
基本实现和DES类似,只不过在实现该算法的时候,设置密钥长度大于128会出现错误:Illegal key size or default parameters,这是因为美国的出口限制,Sun通过权限文件(local_policy.jar、US_export_policy.jar)做了相应限制,Oracle在其官方网站上提供了无政策限制权限文件(Unlimited Strength Jurisdiction Policy Files),我们只需要将其部署在JRE环境中,就可以解决限制问题
JDK8的无政策限制权限文件(http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html)
将下载的local_policy.jar和US_export_policy.jar替换JDK的JRE环境中,或者是JRE环境中上述两个jar文件即可
非对称的ELGamal加密算法算法也有该问题,解决方法相同
加密的数据:
private static String src="Hello AES";
导入的类:
import java.security.Key;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
JDK的实现:
public static void jdkAES(){
try {
//生成key
KeyGenerator keyGenerator=KeyGenerator.getInstance("AES");
keyGenerator.init(new SecureRandom());
SecretKey secretKey = keyGenerator.generateKey();
byte[] key1 = secretKey.getEncoded();
//key转换为密钥
Key key2 = new SecretKeySpec(key1, "AES");
//加密
Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5padding");
cipher.init(Cipher.ENCRYPT_MODE, key2);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("jdkAES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE, key2);
result = cipher.doFinal(result);
System.out.println("jdkAES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
bc的实现(同样使用了添加provider的做法):
public static void bcAES(){
try {
Security.addProvider(new BouncyCastleProvider());
//生成key
KeyGenerator keyGenerator=KeyGenerator.getInstance("AES", "BC");
keyGenerator.getProvider();
keyGenerator.init(128); //显示指定密钥长度
SecretKey secretKey = keyGenerator.generateKey();
byte[] key1 = secretKey.getEncoded();
//key转换为密钥
Key key2 = new SecretKeySpec(key1, "AES");
//加密
Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5padding");
cipher.init(Cipher.ENCRYPT_MODE, key2);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("jdkAES加密: "+Hex.encodeHexString(result)); //转换为十六进制
//解密
cipher.init(Cipher.DECRYPT_MODE, key2);
result = cipher.doFinal(result);
System.out.println("jdkAES解密: "+new String(result)); //转换字符串
} catch (Exception e) {
e.printStackTrace();
}
}
基于口令的对称加密算法(它其实是对之前的算法的包装,比如说MD5和DES,我这里就是的是对MD5和DES包装的PBE算法,还有其他类型的PBE),口令就是我们俗话说的密码,PBE中有一个salt(盐)的概念,盐就是干扰码
加密的数据:
private static String src="Hello PBE";
导入的类:
import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import org.apache.commons.codec.binary.Base64;
JDk的实现:
public static void jdkPBE(){
try {
//初始化盐
SecureRandom random=new SecureRandom();
byte[] salt = random.generateSeed(8); //指定为8位的盐 (盐就是干扰码,通过添加干扰码增加安全)
//口令和密钥
String password="lynu"; //口令
PBEKeySpec pbeKeySpec=new PBEKeySpec(password.toCharArray());
SecretKeyFactory factory=SecretKeyFactory.getInstance("PBEWITHMD5andDES");
Key key=factory.generateSecret(pbeKeySpec); //密钥
//加密
PBEParameterSpec pbeParameterSpec=new PBEParameterSpec(salt, 100); //参数规范,第一个参数是盐,第二个是迭代次数(经过散列函数多次迭代)
Cipher cipher=Cipher.getInstance("PBEWITHMD5andDES");
cipher.init(Cipher.ENCRYPT_MODE, key,pbeParameterSpec);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("jdk PBE加密: "+Base64.encodeBase64String(result));
//解密
cipher.init(Cipher.DECRYPT_MODE, key,pbeParameterSpec);
result = cipher.doFinal(result);
System.out.println("jdk PBE解密: "+new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}
非对称算法就是发送方和接收方的密钥是不一样的,非对称相对于对称来说,有公钥和私钥的概念,基本上公钥是公开的,比如会在网络上传输,而私钥安全性要求就要高很多了,因为私钥是要保密的
基本的非对称算法有DH,RSA,ELGamal算法
基于交换交换的非对称算法,接收方需要得到接收方的key构建本地密钥,而接收方也需要得到发送方的key构建自己本地的密钥。只有JDK的实现
需要加密的数据:
private static String src="Hello DH";
需要导入的类:
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;
import java.util.Objects;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.SecretKey;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
JDK的实现:
public static void jdkDH(){
try {
//初始化发送方密钥
KeyPairGenerator senderKeyPairGenerator=KeyPairGenerator.getInstance("DH");
senderKeyPairGenerator.initialize(512); //密钥长度
KeyPair senderKeyPair = senderKeyPairGenerator.generateKeyPair();
byte[] senderPublicKeyEnc = senderKeyPair.getPublic().getEncoded(); //发送方key,需传递给接收方(网络,文件)
//初始化接收方密钥
KeyFactory factory=KeyFactory.getInstance("DH");
X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(senderPublicKeyEnc); //根据从发送方得到的key解析
PublicKey receiverPublicKey=factory.generatePublic(x509EncodedKeySpec);
DHParameterSpec dhParameterSpec=((DHPublicKey)receiverPublicKey).getParams();
KeyPairGenerator receiverKeyPairGenerator=KeyPairGenerator.getInstance("DH");
receiverKeyPairGenerator.initialize(dhParameterSpec);
KeyPair receiverKeyPair = receiverKeyPairGenerator.generateKeyPair();
PrivateKey receiverPrivateKey = receiverKeyPair.getPrivate();
byte[] receiverPublicKeyEnc = receiverKeyPair.getPublic().getEncoded();
//密钥构建
KeyAgreement receiverKeyAgreement=KeyAgreement.getInstance("DH");
receiverKeyAgreement.init(receiverPrivateKey);
receiverKeyAgreement.doPhase(receiverPublicKey, true);
SecretKey receiverDESKey=receiverKeyAgreement.generateSecret("DES"); //发送发密钥(公钥)
KeyFactory senderKeyFactory=KeyFactory.getInstance("DH");
x509EncodedKeySpec=new X509EncodedKeySpec(receiverPublicKeyEnc);
PublicKey senderPublicKey=senderKeyFactory.generatePublic(x509EncodedKeySpec);
KeyAgreement senderKeyAgreement=KeyAgreement.getInstance("DH");
senderKeyAgreement.init(senderKeyPair.getPrivate());
senderKeyAgreement.doPhase(senderPublicKey, true);
SecretKey senderDESKey=senderKeyAgreement.generateSecret("DES"); //接收方密钥(私钥)
if(Objects.equals(receiverDESKey, senderDESKey)){
System.out.println("双方密钥相同");
}
//加密
Cipher cipher=Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, senderDESKey);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("jdk DH加密: "+org.apache.commons.codec.binary.Base64.encodeBase64String(result));
//解密
cipher.init(Cipher.DECRYPT_MODE, receiverDESKey);
result=cipher.doFinal(result);
System.out.println("jdk DH解密: "+new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}
RSA相较于DH算法的实现简单,适用范围较广,公钥和私钥的创建较简单,而且支持公钥加密,私钥解密或者是私钥加密,公钥解密两种方式
要加密的数据:
private static String src="Hello RSA";
要导入的类:
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.codec.binary.Base64;
JDK的实现,公钥加密,私钥解密和私钥加密,公钥解密两种方式:
public static void jdkRSA(){
try {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(512);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey=(RSAPublicKey) keyPair.getPublic(); //公钥
RSAPrivateKey rsaPrivateKey=(RSAPrivateKey) keyPair.getPrivate(); //私钥
System.out.println("public key:"+Base64.encodeBase64String(rsaPublicKey.getEncoded()));
System.out.println("private key:"+Base64.encodeBase64String(rsaPrivateKey.getEncoded()));
//私钥加密,公钥解密--加密
PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Cipher cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("RSA私钥加密,公钥解密--加密:"+Base64.encodeBase64String(result));
//私钥加密,公钥解密--解密
X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());
keyFactory=KeyFactory.getInstance("RSA");
PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);
cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE,publicKey);
result = cipher.doFinal(result);
System.out.println("RSA私钥加密,公钥解密--解密:"+new String(result));
//公钥加密,私钥解密--加密
x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());
keyFactory=KeyFactory.getInstance("RSA");
publicKey=keyFactory.generatePublic(x509EncodedKeySpec);
cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE,publicKey);
result = cipher.doFinal(src.getBytes());
System.out.println("RSA公钥加密,私钥解密--加密:"+Base64.encodeBase64String(result));
//公钥加密,私钥解密--解密
pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
keyFactory=KeyFactory.getInstance("RSA");
privateKey =keyFactory.generatePrivate(pkcs8EncodedKeySpec);
cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE,privateKey);
result=cipher.doFinal(result);
System.out.println("RSA公钥加密,私钥解密--解密:"+new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}
ELGamal算法的和AES一样存在密钥长度的限制,解决方法和AES一致。不过ELGamal只支持公钥加密,私钥解密这种方式。只有bc的实现方式
要加密的数据:
private static String src="Hello ELGamal";
导入的类:
import java.security.AlgorithmParameterGenerator;
import java.security.AlgorithmParameters;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import javax.crypto.spec.DHParameterSpec;
import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
bc的实现方式:
public static void bcELGamal(){
try {
//加载provider
Security.addProvider(new BouncyCastleProvider());
//初始化密钥
AlgorithmParameterGenerator algorithmParameterGenerator=AlgorithmParameterGenerator.getInstance("ELGamal");
algorithmParameterGenerator.init(256);
AlgorithmParameters algorithmParameters=algorithmParameterGenerator.generateParameters();
DHParameterSpec dhParameterSpec=(DHParameterSpec)algorithmParameters.getParameterSpec(DHParameterSpec.class);
KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("ELGamal");
keyPairGenerator.initialize(dhParameterSpec, new SecureRandom());
KeyPair keyPair=keyPairGenerator.generateKeyPair();
PublicKey elGamalPublicKey=keyPair.getPublic(); //公钥
PrivateKey elGamalPrivateKey=keyPair.getPrivate(); //私钥
System.out.println("public key:"+Base64.encodeBase64String(elGamalPublicKey.getEncoded()));
System.out.println("private key:"+Base64.encodeBase64String(elGamalPrivateKey.getEncoded()));
//公钥加密,私钥解密--加密
X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(elGamalPublicKey.getEncoded());
KeyFactory keyFactory=KeyFactory.getInstance("ELGamal");
PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);
Cipher cipher=Cipher.getInstance("ELGamal");
cipher.init(Cipher.ENCRYPT_MODE,publicKey);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("ELGamal加密:"+Base64.encodeBase64String(result));
//公钥加密,私钥解密--解密
PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(elGamalPrivateKey.getEncoded());
keyFactory=KeyFactory.getInstance("ELGamal");
PrivateKey privateKey =keyFactory.generatePrivate(pkcs8EncodedKeySpec);
cipher=Cipher.getInstance("ELGamal");
cipher.init(Cipher.DECRYPT_MODE,privateKey);
result=cipher.doFinal(result);
System.out.println("ElGamal解密:"+new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}
作者:OverZeal
出处:https://www.cnblogs.com/lz2017/p/6917049.html
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