JAVA对数字证书的常用操作

JAVA对数字证书的常用操作Java是一个面向对象的语言。对程序员来说，这意味着要注意应中的数据和操纵数据的方法(method)，而不是严格地用过程来思考。以下是关于JAVA对数字证书的常用操作，欢迎大家参考!一：需要包含的包importjava.security.*;importjava.io.*;importjava.util.*;importjava.security.*;importjava.security.cert.*;importsun.security.x509.*importjava.security.cert.Certificate;importjava.security.cert.CertificateFactory;二：从文件中读取证书用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CertificateFactorycf=CertificateFactory.getInstance("X.509");FileInputStreamin=newFileInputStream("out.csr");Certificatec=cf.generateCertificate(in);Strings=c.toString();三：从密钥库中直接读取证书Stringpass="123456";FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=KeyStore.getInstance("JKS");ks.load(in,pass.toCharArray());java.security.cert.Certificatec=ks.getCertificate(alias);//alias为条目的别名四：JAVA程序中显示证书指定信息System.out.println("输出证书信息:\n"+c.toString());System.out.println("版本号:"+t.getVersion());System.out.println("序列号:"+t.getSerialNumber().toString(16));System.out.println("主体名："+t.getSubjectDN());System.out.println("签发者："+t.getIssuerDN());System.out.println("有效期："+t.getNotBefore());System.out.println("签名算法："+t.getSigAlgName());byte[]sig=t.getSignature();//签名值PublicKeypk=t.getPublicKey();byte[]pkenc=pk.getEncoded();System.out.println("公钥");for(inti=0;i<pkenc.length;i++)System.out.print(pkenc[i]+",");五：JAVA程序列出密钥库所有条目Stringpass="123456";FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=KeyStore.getInstance("JKS");ks.load(in,pass.toCharArray());Enumeratione=ks.aliases();while(e.hasMoreElements())java.security.cert.Certificatec=ks.getCertificate((String)e.nextElement());六：JAVA程序修改密钥库口令Stringoldpass="123456";Stringnewpass="654321";FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=KeyStore.getInstance("JKS");ks.load(in,oldpass.toCharArray());in.close();FileOutputStreamoutput=newFileOutputStream(".keystore");ks.store(output,newpass.toCharArray());output.close();七：JAVA程序修改密钥库条目的口令及添加条目FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=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PrivateKeypk=(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FileOutputStreamoutput=newFileOutputStream("another");ks.store(output,storepass.toCharArray())将keystore对象内容写入新文件八：JAVA程序检验别名和删除条目FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=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FileOutputStreamoutput=newFileOutputStream(".keystore");ks.store(output,storepass.toCharArray())将keystore对象内容写入文件,条目删除成功九：JAVA程序签发数字证书(1)从密钥库中读取CA的证书FileInputStreamin=newFileInputStream(".keystore");KeyStoreks=KeyStore.getInstance("JKS");ks.load(in,storepass.toCharArray());java.security.cert.Certificatec1=ks.getCertificate("caroot");(2)从密钥库中读取CA的私钥PrivateKeycaprk=(PrivateKey)ks.getKey(alias,cakeypass.toCharArray());(3)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X509CertImplcimp1=newX509CertImpl(encod1);用该编码创建X509CertImpl类型对象X509CertInfocinfo1=(X509CertInfo)cimp1.get(X509CertImpl.NAME+"."+X509CertImpl.INFO);获取X509CertInfo对象X500Nameissuer=(X500Name)cinfo1.get(X509CertInfo.SUBJECT+"."+CertificateIssuerName.DN_NAME);获取X509Name类型的签发者信息(4)获取待签发的证书CertificateFactorycf=CertificateFactory.getInstance("X.509");FileInputStreamin2=newFileInputStream("user.csr");java.security.cert.Certificatec2=cf.generateCertificate(in);(5)从待签发的证书中提取证书信息byte[]encod2=c2.getEncoded();X509CertImplcimp2=newX509CertImpl(encod2);用该编码创建X509CertImpl类型对象X509CertInfocinfo2=(X509CertInfo)cimp2.get(X509CertImpl.NAME+"."+X509CertImpl.INFO);获取X509CertInfo对象(6)设置新证书有效期Datebegindate=newDate();获取当前时间Dateenddate=newDate(begindate.getTime()+3000*24*60*60*1000L);有效期为3000天CertificateValiditycv=newCertificateValidity(begindate,enddate);创建对象cinfo2.set(X509CertInfo.VALIDITY,cv);设置有效期(7)设置新证书序列号intsn=(int)(begindate.getTime()/1000);以当前时间为序列号CertificateSerialNumbercsn=newCertificateSerialNumber(sn);cinfo2.set(X509CertInfo.SERIAL_NUMBER,csn);(8)设置新证书签发者cinfo2.set(X509CertInfo.ISSUER+"."+CertificateIssuerName.DN_NAME,issuer);应用第三步的结果(9)设置新证书签名算法信息AlgorithmIdalgorithm=newAlgorithmId(AlgorithmId.md5WithRSAEncryption_oid);cinfo2.set(CertificateAlgorithmId.NAME+"."+CertificateAlgorithmId.ALGORITHM,algorithm);(10)创建证书并使用CA的私钥对其签名X509CertImplnewcert=newX509CertImpl(cinfo2);newcert.sign(caprk,"MD5WithRSA");使用CA私钥对其签名(11)将新证书写入密钥库ks.setCertificateEntry("lf_signed",newcert);FileOutputStreamout=newFileOutputStream("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十：数字证书的检验(1)验证证书的有效期(a)获取X509Certificate类型对象CertificateFactorycf=CertificateFactory.getInstance("X.509");FileInputStreamin1=newFileInputStream("aa.crt");java.security.cert.Certificatec1=cf.generateCertificate(in1);X509Certificatet=(X509Certificate)c1;in2.close();(b)获取日期DateTimeNow=newDate();(c)检验有效性try{t.checkValidity(TimeNow);System.out.println("OK");}catch(CertificateExpiredExceptione){//过期System.o