柯克霍夫原则:数据的安全基于密钥而不是算法的保密。即系统的安全取决于密钥,对密钥保密,对算法公开。——现代密码学设计的基本原则。
算法实现分为3类:jdk,Common Codes(CC),Bouncy Castle(BC),后两者使用需要引入jar包。
1.Base64
1.jdk实现
BASE64Encoder encoder = new BASE64Encoder();
String encode = encoder.encode(src.getBytes());
System.out.println("jdk encode:"+encode);
BASE64Decoder decoder = new BASE64Decoder();
System.out.println("jdk decode:"+new String(decoder.decodeBuffer(encode)));
2.CC实现:
byte[] encodeBytes = Base64.encodeBase64(src.getBytes());
System.out.println("cc encode:"+new String(encodeBytes));
System.out.println("cc decode:"+new String(Base64.decodeBase64(encodeBytes)));
3.BC实现
byte[] encodeBytes = org.bouncycastle.util.encoders.Base64.encode(src.getBytes());
byte[] decodeBytes = org.bouncycastle.util.encoders.Base64.decode(encodeBytes);
2.MD算法
1.jdk实现:
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] mdBytes = md.digest(src.getBytes());
System.out.println("jdk md5:"+Hex.encodeHexString(mdBytes));
其中Hex是引入的第三包cc中的类。
2.CC实现
System.out.println("cc md5:"+DigestUtils.md5Hex(src.getBytes()));
3.BC实现
Digest digest = new MD5Digest();
digest.update(src.getBytes(),0,src.getBytes().length);
byte[] mdBytes = new byte[digest.getDigestSize()];
digest.doFinal(mdBytes,0);
System.out.println("bc md5:"+org.bouncycastle.util.encoders.Base64.Hex.toHexString(myBytes));
其中的Hex是封装在BC包中的。
3.SHA算法
SHA算法实现与MD实现很相似
1.jdk实现
MessageDigest md = MessageDigest.getInstance("SHA");
byte[] mdBytes = md.digest(src.getBytes());
System.out.println("jdk sha1:"+Hex.encodeHexString(mdBytes));
2.cc实现
System.out.println("cc sha1:"+DigestUtils.sha1Hex(src.getBytes()));
3.bc实现
Digest digest = new SHA1Digest();
digest.update(src.getBytes(),0,src.getBytes().length);
byte[] mdBytes = new byte[digest.getDigestSize()];
digest.doFinal(mdBytes,0);
System.out.println("bc SHA1:"+org.bouncycastle.util.encoders.Base64.Hex.toHexString(myBytes));
4.MAC算法
MAC分为mac与hmac,是MD与SHA的融合。
KeyGennerator kg = KeyGenerator.getInstance("HmacMD5");
SecretKey sk = kg.generateKey();//产生密钥
//byte[]key = sk.getEncoded(); //获得密钥,随机
byte[]key = Hex.decodeHex(new char[]{'a','a','a','a','a','a','a','a'});//获得密钥,自定义
SecretKey rsk = new SecretKeySpec(key, "HmacMD5");//还原密钥
Mac mac = Mac.getInstance(rsk.getAlgorithm());//实例化mac
mac.init(rsk);
byte[] hmacMD5Bytes = mac.doFinal(src.getBytes());//执行摘要
System.out.println("jdk hamcMD5:"+Hex.encodeHexString(hmacMD5Bytes));