java操作数字证书

1.用keytool将.keystore中的证书写入文件中，然后从该文件中读取证书信息

CertificateFactory cf=CertificateFactory.getInstance("X.509");FileInputStream in=new FileInputStream("out.csr");Certificate c=cf.generateCertificate(in); String s=c.toString();

 

2.从密钥库中直接读取证书

String pass="123456";FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,pass.toCharArray());java.security.cert.Certificate c=ks.getCertificate(alias);//alias为条目的别名

 

3.JAVA程序列出密钥库所有条目

String pass="123456";FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,pass.toCharArray());Enumeration e=ks.aliases();while(e.hasMoreElements())    java.security.cert.Certificate c=ks.getCertificate((Stringe.nextElement()); 

 

4.JAVA程序修改密钥库口令

String oldpass="123456";String newpass="654321";FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,oldpass.toCharArray());in.close();FileOutputStream output=new FileOutputStream(".keystore");ks.store(output,newpass.toCharArray());output.close();

 

 5. JAVA程序修改密钥库条目的口令及添加条目 

FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,storepass.toCharArray());Certificate [] cchain=ks.getCertificate(alias);//获取别名对应条目的证书链PrivateKey pk=(PrivateKey)ks.getKey(alias,oldkeypass.toCharArray());//获取别名对应条目的私钥ks.setKeyEntry(alias,pk,newkeypass.toCharArray(),cchain);//向密钥库中添加条目,第一个参数指定所添加条目的别名，假如使用已存在别名将覆盖已存在条目，使用新别名将增加一个新条目，第二个参数为条目的私钥，第三个为设置的新口令，第四个为该私钥的公钥的证书链FileOutputStream output=new FileOutputStream("another");ks.store(output,storepass.toCharArray());//将keystore对象内容写入新文件

6.JAVA程序检验别名和删除条目 

FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,storepass.toCharArray());ks.containsAlias("sage");//检验条目是否在密钥库中，存在返回trueks.deleteEntry("sage");//删除别名对应的条目FileOutputStream output=new FileOutputStream(".keystore");ks.store(output,storepass.toCharArray());//将keystore对象内容写入文件,条目删除成功

  

7.JAVA程序签发数字证书

//从密钥库中读取CA的证书FileInputStream in=new FileInputStream(".keystore");KeyStore ks=KeyStore.getInstance("JKS");ks.load(in,storepass.toCharArray());java.security.cert.Certificate c1=ks.getCertificate("caroot");//从密钥库中读取CA的私钥PrivateKey caprk=(PrivateKey)ks.getKey(alias,cakeypass.toCharArray());//从CA的证书中提取签发者的信息byte[] encod1=c1.getEncoded(); 提取CA证书的编码X509CertImpl cimp1=new X509CertImpl(encod1); 用该编码创建X509CertImpl类型对象X509CertInfo cinfo1=(X509CertInfo)cimp1.get(X509CertImpl.NAME+"."+X509CertImpl.INFO); 获取X509CertInfo对象X500Name issuer=(X500Name)cinfo1.get(X509CertInfo.SUBJECT+"."+CertificateIssuerName.DN_NAME); 获取X509Name类型的签发者信息//获取待签发的证书CertificateFactory cf=CertificateFactory.getInstance("X.509");FileInputStream in2=new FileInputStream("user.csr");java.security.cert.Certificate c2=cf.generateCertificate(in);//从待签发的证书中提取证书信息byte [] encod2=c2.getEncoded();X509CertImpl cimp2=new X509CertImpl(encod2); //用该编码创建X509CertImpl类型对象X509CertInfo cinfo2=(X509CertInfo)cimp2.get(X509CertImpl.NAME+"."+X509CertImpl.INFO); //获取X509CertInfo对象//设置新证书有效期Date begindate=new Date(); //获取当前时间Date enddate=new Date(begindate.getTime()+3000*24*60*60*1000L); //有效期为3000天CertificateValidity cv=new CertificateValidity(begindate,enddate); //创建对象cinfo2.set(X509CertInfo.VALIDITY,cv); //设置有效期//设置新证书序列号int sn=(int)(begindate.getTime()/1000); //以当前时间为序列号CertificateSerialNumber csn=new CertificateSerialNumber(sn);cinfo2.set(X509CertInfo.SERIAL_NUMBER,csn);//设置新证书签发者cinfo2.set(X509CertInfo.ISSUER+"."+CertificateIssuerName.DN_NAME,issuer);//应用第三步的结果//设置新证书签名算法信息AlgorithmId algorithm=new AlgorithmId(AlgorithmId.md5WithRSAEncryption_oid);cinfo2.set(CertificateAlgorithmId.NAME+"."+CertificateAlgorithmId.ALGORITHM,algorithm);//创建证书并使用CA的私钥对其签名X509CertImpl newcert=new X509CertImpl(cinfo2);newcert.sign(caprk,"MD5WithRSA"); //使用CA私钥对其签名//将新证书写入密钥库ks.setCertificateEntry("lf_signed",newcert);FileOutputStream out=new FileOutputStream("newstore");ks.store(out,"newpass".toCharArray()); //这里是写入了新的密钥库，也可以使用第七条来增加条目

 

8.数字证书的检验

//验证证书的有效期//获取X509Certificate类型对象CertificateFactory cf=CertificateFactory.getInstance("X.509");FileInputStream in1=new FileInputStream("aa.crt");java.security.cert.Certificate c1=cf.generateCertificate(in1);X509Certificate t=(X509Certificate)c1;in2.close();Date TimeNow=new Date();//检验有效性t.checkValidity(TimeNow);//验证证书签名的有效性CertificateFactory cf=CertificateFactory.getInstance("X.509");FileInputStream in2=new FileInputStream("caroot.crt");java.security.cert.Certificate cac=cf.generateCertificate(in2);in2.close();//获取CA的公钥PublicKey pbk=cac.getPublicKey();c1.verify(pbk);