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 rity. * ;

import . * ;

import . * ;

import rity. * ;

import . * ;

import rity.x509. *

import ificate;

import ificateFactory;

　　二：从文件中读取证书

用keytool将tore中的证书写入文件中，然后从该文件中读取证书信息

CertificateFactory cf = nstance( " X.509 " );

FileInputStream in = new FileInputStream( " " );

Certificate c = rateCertificate(in);

String s = ring();

　　三：从密钥库中直接读取证书

String pass = " 123456 " ;

FileInputStream in = new FileInputStream( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

ificate c = ertificate(alias); // alias为条目的别名

　　四：JAVA程序中显示证书指定信息

tln( " 输出证书信息:n " + ring());

tln( " 版本号: " + ersion());

tln( " 序列号: " + erialNumber()ring( 16 ));

tln( " 主体名： " + ubjectDN());

tln( " 签发者： " + ssuerDN());

tln( " 有效期： " + otBefore());

tln( " 签名算法： " + igAlgName());

byte [] sig = ignature(); // 签名值

PublicKey pk = ublicKey();

byte [] pkenc = ncoded();

tln( " 公钥 " );

for ( int i = 0 ;i < th;i ++ )t(pkenc[i] + " , " );

　　五：JAVA程序列出密钥库所有条目

String pass = " 123456 " ;

FileInputStream in = new FileInputStream( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

Enumeration e = ses();

while (oreElements())

ificate c = ertificate((String)Element());

　　六：JAVA程序修改密钥库口令

String oldpass = " 123456 " ;

String newpass = " 654321 " ;

FileInputStream in = new FileInputStream( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

e();

FileOutputStream output = new FileOutputStream( " tore " );

e(output,arArray());

e();

　　七：JAVA程序修改密钥库条目的口令及添加条目

FileInputStream in = new FileInputStream( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

Certificate [] cchain = ertificate(alias);获取别名对应条目的证书链

PrivateKey pk = (PrivateKey)ey(alias,arArray());获取别名对应条目的私钥

eyEntry(alias,pk,arArray(),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");

e(output,arArray())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( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

ainsAlias( " sage " );检验条目是否在密钥库中，存在返回true

teEntry( " sage " );删除别名对应的条目

FileOutputStream output = new FileOutputStream( " tore " );

e(output,arArray())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( " tore " );

KeyStore ks = nstance( " JKS " );

(in,arArray());

ificate c1 = ertificate( " caroot " );

(2)从密钥库中读取CA的私钥

PrivateKey caprk = (PrivateKey)ey(alias,arArray());

(3)从CA的证书中提取签发者的信息

byte [] encod1 = ncoded(); 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)( + " . " + ); 获取X509CertInfo对象

X500Name issuer = (X500Name)(ECT + " . " + _NAME); 获取X509Name类型的'签发者信息

(4)获取待签发的证书

CertificateFactory cf = nstance( " X.509 " );

FileInputStream in2 = new FileInputStream( " " );

ificate c2 = rateCertificate(in);

(5)从待签发的证书中提取证书信息

byte [] encod2 = ncoded();

X509CertImpl cimp2 = new X509CertImpl(encod2); 用该编码创建X509CertImpl类型对象

X509CertInfo cinfo2 = (X509CertInfo)( + " . " + ); 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(ime() + 3000 * 24 * 60 * 60 * 1000L ); 有效期为3000天

CertificateValidity cv = new CertificateValidity(begindate,enddate); 创建对象

(DITY,cv); 设置有效期

(7)设置新证书序列号

int sn = ( int )(ime() / 1000 ); 以当前时间为序列号

CertificateSerialNumber csn = new CertificateSerialNumber(sn);

(AL_NUMBER,csn);

(8)设置新证书签发者

(ER+"."+_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(5WithRSAEncryption_oid);

(+"."+RITHM,algorithm);

(10)创建证书并使用CA的私钥对其签名

X509CertImpl newcert=new X509CertImpl(cinfo2);

(caprk,"MD5WithRSA"); 使用CA私钥对其签名

(11)将新证书写入密钥库

ertificateEntry( " lf_signed " ,newcert);

FileOutputStream out = new FileOutputStream( " newstore " );

e(out, " newpass " arArray()); 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 = nstance( " X.509 " );

FileInputStream in1 = new FileInputStream( " " );

ificate c1 = rateCertificate(in1);

X509Certificate t = (X509Certificate)c1;

e();

(b)获取日期

Date TimeNow=new Date();

(c)检验有效性

try {

kValidity(TimeNow);

tln( " OK " );

} catch (CertificateExpiredException e) { // 过期

tln( " Expired " );

tln(essage());

} catch ((CertificateNotYetValidException e) { // 尚未生效

tln( " Too early " );

tln(essage());}

(2)验证证书签名的有效性

(a)获取CA证书

CertificateFactory cf = nstance( " X.509 " );

FileInputStream in2 = new FileInputStream( " " );

ificate cac = rateCertificate(in2);

e();

(c)获取CA的公钥

PublicKey pbk=ublicKey();

(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 {

fy(pbk);

pass = true ;

} catch (Exception e) {

pass = false ;

tln(e);