- 相关推荐
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
import java.security. * ;
import java.io. * ;
import java.util. * ;
import java.security. * ;
import java.security.cert. * ;
import sun.security.x509. *
import java.security.cert.Certificate;
import java.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
CertificateFactory cf = CertificateFactory.getInstance( " X.509 " );
FileInputStream in = new FileInputStream( " out.csr " );
Certificate c = cf.generateCertificate(in);
String s = c.toString();
三：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
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
PublicKey pk = t.getPublicKey();
byte [] pkenc = pk.getEncoded();
System.out.println( " 公钥 " );
for ( int i = 0 ;i < pkenc.length;i ++ )System.out.print(pkenc[i] + " , " );
五：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((String)e.nextElement());
六：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();
七：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
八：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true
ks.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
九：JAVA程序签发数字证书
(1)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 " );
(2)从密钥库中读取CA的私钥
PrivateKey caprk = (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
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
(4)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);
(5)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
(6)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
(7)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);
(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
AlgorithmId algorithm=new AlgorithmId(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
X509CertImpl newcert=new X509CertImpl(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);
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
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
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();
(b)获取日期
Date TimeNow=new Date();
(c)检验有效性
try {
t.checkValidity(TimeNow);
System.out.println( " OK " );
} catch (CertificateExpiredException e) { // 过期
System.out.println( " Expired " );
System.out.println(e.getMessage());
} catch ((CertificateNotYetValidException e) { // 尚未生效
System.out.println( " Too early " );
System.out.println(e.getMessage());}
(2)验证证书签名的有效性
(a)获取CA证书
CertificateFactory cf = CertificateFactory.getInstance( " X.509 " );
FileInputStream in2 = new FileInputStream( " caroot.crt " );
java.security.cert.Certificate cac = cf.generateCertificate(in2);
in2.close();
(c)获取CA的公钥
PublicKey pbk=cac.getPublicKey();
(b)获取待检验的证书(上步已经获取了，就是C1)
(c)检验证书
boolean pass = false ;
try {
c1.verify(pbk);
pass = true ;
} catch (Exception e) {
pass = false ;
System.out.println(e);
【JAVA对数字证书的常用操作】相关文章：
java关于多线程的操作11-06
JAVA IO操作知识汇总06-21
2016年java数组操作方法大全06-10
java操作xml的一个小例子08-01
Java枚举的常用方法09-06
电脑常用操作技巧07-19
常用的Word操作技巧09-11
Java数组定义常用方法08-29
Java反射机制常用API09-04