Java加密算法-公钥加密私钥解密

package com.cn.ssl; import java.io.*; import java.security.*; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import javax.crypto.Cipher; import javax.crypto.KeyAgreement; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.interfaces.DHPublicKey; import javax.crypto.spec.DHParameterSpec; import javax.crypto.spec.SecretKeySpec; public class myDigest { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub myDigest my=new myDigest(); my.testDigest(); } public void testDigest() { try { String myinfo="我的测试信息"; MessageDigest alg = MessageDigest.getInstance("MD5"); MessageDigest alga = MessageDigest.getInstance("SHA-1"); alga.update(myinfo.getBytes()); byte[] digesta=alga.digest(); System.out.println("本信息摘要是:"+byte2hex(digesta)); //通过某中方式传给其他人你的信息 MessageDigest algb = MessageDigest.getInstance("SHA-1"); algb.update(myinfo.getBytes()); if(algb.isEqual(digesta,algb.digest())) { System.out.println("信息检查正常"); } else { System.out.println("摘要不相同"); } } catch (NoSuchAlgorithmException ex) { System.out.println("非法摘要算法"); } } public String byte2hex(byte[] b) //二行制转字符串 { String hs=""; String stmp=""; for (int n=0;n<b.length;n++) { stmp=(Integer.toHexString(b[n] & 0XFF)); if (stmp.length()==1) hs=hs+"0"+stmp; else hs=hs+stmp; } return hs.toUpperCase(); } //我自己乱写的方法 public void dsa() { try { KeyPairGenerator keygen = KeyPairGenerator.getInstance("DSA"); SecureRandom secrand=new SecureRandom(); secrand.setSeed("tttt".getBytes()); //初始化随机产生器 keygen.initialize(512,secrand); //初始化密钥生成器 //keygen.initialize(512); KeyPair keys=keygen.generateKeyPair(); //生成密钥组 PublicKey pubkey=keys.getPublic(); PrivateKey prikey=keys.getPrivate(); ObjectInputStream in=new ObjectInputStream(new FileInputStream("e:/qhc/tools/myprikey.dat")); PrivateKey myprikey= (PrivateKey)in.readObject(); in.close(); String myinfo="要加密的信息"; Signature signet=Signature.getInstance("DSA"); signet.initSign(myprikey); signet.update(myinfo.getBytes()); byte[] signed=signet.sign(); ObjectOutputStream out1=new ObjectOutputStream(new FileOutputStream("e:/qhc/tools/myinfo.dat")); out1.writeObject(myinfo); out1.writeObject(signed); out1.close(); byte[] bobEncodedPubKey=pubkey.getEncoded(); //生成编码 //传送二进制编码 //以下代码转换编码为相应key对象 X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(bobEncodedPubKey); KeyFactory keyFactory = KeyFactory.getInstance("DSA"); PublicKey bobPubKey = keyFactory.generatePublic(bobPubKeySpec); byte[] bPKCS = myprikey.getEncoded(); //传送二进制编码 //以下代码转换编码为相应key对象 PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(bPKCS); KeyFactory keyf = KeyFactory.getInstance("DSA"); PrivateKey otherprikey = keyf.generatePrivate(priPKCS8); // KeyGenerator keygen1 = KeyGenerator.getInstance("DSA"); SecretKey deskey = keygen1.generateKey(); Cipher c1 = Cipher.getInstance("DSA"); c1.init(Cipher.ENCRYPT_MODE,deskey); byte[] cipherByte=c1.doFinal(myinfo.getBytes()); c1 = Cipher.getInstance("DSA"); c1.init(Cipher.DECRYPT_MODE,deskey); byte[] clearByte=c1.doFinal(cipherByte); SecretKey deskey1 = keygen1.generateKey(); byte[] desEncode=deskey.getEncoded(); SecretKeySpec destmp1=new SecretKeySpec(desEncode,"DSA"); SecretKey mydeskey=destmp1; System.out.println("ALICE: 产生 DH 对 ..."); KeyPairGenerator aliceKpairGen = KeyPairGenerator.getInstance("DH"); aliceKpairGen.initialize(512); KeyPair aliceKpair = aliceKpairGen.generateKeyPair(); DHParameterSpec dhParamSpec = ((DHPublicKey)pubkey).getParams(); KeyPairGenerator bobKpairGen = KeyPairGenerator.getInstance("DH"); bobKpairGen.initialize(dhParamSpec); KeyPair bobKpair = bobKpairGen.generateKeyPair(); KeyAgreement bobKeyAgree = KeyAgreement.getInstance("DH"); bobKeyAgree.init(bobKpair.getPrivate()); bobKeyAgree.doPhase(pubkey, true); SecretKey bobDesKey = bobKeyAgree.generateSecret("DES"); byte[] bobPubKeyEnc = bobKpair.getPublic().getEncoded(); KeyAgreement aliceKeyAgree = KeyAgreement.getInstance("DH"); aliceKeyAgree.init(aliceKpair.getPrivate()); aliceKeyAgree.doPhase(bobPubKey, true); SecretKey aliceDesKey = aliceKeyAgree.generateSecret("DES"); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void signature() { /* public abstract KeyPair generateKeyPair() 产生新密钥对 Java.security.KeyPair 密钥对类 public PrivateKey getPrivate() 返回私钥 public PublicKey getPublic() 返回公钥 Java.security.Signature 签名类 public static Signature getInstance(String algorithm) throws NoSuchAlgorithmException 返回一个指定算法的Signature对象 参数 algorithm 如:"DSA" public final void initSign(PrivateKey privateKey) throws InvalidKeyException 用指定的私钥初始化 参数:privateKey 所进行签名时用的私钥 public final void update(byte data) throws SignatureException public final void update(byte[] data) throws SignatureException public final void update (byte[] data, int off, int len) throws SignatureException 添加要签名的信息 public final byte[] sign() throws SignatureException 返回签名的数组， 前提是initSign和update public final void initVerify (PublicKey publicKey) throws InvalidKeyException 用指定的公钥初始化 参数:publicKey 验证时用的公钥 public final boolean verify (byte[] signature) throws SignatureException 验证签名是否有效， 前提是已经initVerify初始化 参数: signature 签名数组 */ } }