使用OpenSSL创建CA和申请证书

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OpenSSL 简介

OpenSSL 是一种加密工具套件，可实现安全套接字层（SSL v2 / v3）和传输层安全性（TLS v1）网络协议以及它们所需的相关加密标准。

openssl 命令行工具用于从 shell 程序使用 OpenSSL 加密库的各种加密功能。它可以用于：

• 创建和管理私钥，公钥和参数
• 公钥加密操作
• 创建 X.509 证书，CSR 和 CRL
• 消息摘要的计算
• 使用密码进行加密和解密
• SSL / TLS 客户端和服务器测试
• 处理 S / MIME 签名或加密的邮件
• 时间戳记请求，生成和验证

openssl 配置文件及三种策略

 配置文件
/etc/pki/tls/openssl.cnf
 
三种策略
match（匹配）：要求申请填写的信息跟 CA 设置信息必须一致
optional（可选）：可有可无，跟 CA 设置信息可不一致
supplied（提供）：必须填写这项申请信息 

创建私有 CA 和申请、颁发证书文件（以下操作都是在一台机器上执行）

1. 创建所需要的文件

[root@CentOS7 ~]# cd /etc/pki/CA/
[root@CentOS7 CA]# touch index.txt  生成证书索引数据库文件
[root@CentOS7 CA]# echo 01 > serial 指定第一个颁发证书的序列号 

2.CA 自签证书

2.1 生成私钥

[root@CentOS7 CA]# (umask 066;openssl genrsa -out private/cakey.pem 2048)
Generating RSA private key, 2048 bit long modulus
...................................................................................+++
.+++
e is 65537 (0x10001)

2.2 生成自签名证书

[root@CentOS7 CA]# openssl req -new -x509 -key private/cakey.pem -days 3650 -out cacert.pem
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:beijing
Locality Name (eg, city) [Default City]:beijing
Organization Name (eg, company) [Default Company Ltd]:abc
Organizational Unit Name (eg, section) []:IT  
Common Name (eg, your name or your server's hostname) []:hechunping
Email Address []:root@abc.com
 
选项说明：-new：生成新证书签署请求
-x509：专用于 CA 生成自签证书
-key：生成请求时用到的私钥文件
-days n：证书的有效期限
-out /PATH/TO/SOMECERTFILE: 证书的保存路径 

3. 颁发证书

3.1 在需要使用证书的主机生成证书请求（本实验是在本机）

3.1.1 生成私钥

[root@CentOS7 CA]# (umask 066;openssl genrsa -out /data/test.key 2048)
Generating RSA private key, 2048 bit long modulus
..................................................+++
...............................+++
e is 65537 (0x10001)

3.1.2 生成证书申请文件

[root@CentOS7 CA]# openssl req -new -key /data/test.key -out /data/test.csr
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:beijing
Locality Name (eg, city) [Default City]:beijing
Organization Name (eg, company) [Default Company Ltd]:abc
Organizational Unit Name (eg, section) []:IT
Common Name (eg, your name or your server's hostname) []:hechunping
Email Address []:root@abc.com
 
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

3.2 将证书申请文件传输给 CA（两台不同的主机可以使用 scp 命令传输）

3.3CA 签署证书，并将证书颁发给请求者

[root@CentOS7 CA]# openssl ca -in /data/test.csr -out certs/test.crt -days 100
Using configuration from /etc/pki/tls/openssl.cnf
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number: 1 (0x1)
        Validity
            Not Before: Nov 10 13:45:34 2019 GMT
            Not After : Feb 18 13:45:34 2020 GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = beijing
            organizationName          = abc
            organizationalUnitName    = IT
            commonName                = hechunping
            emailAddress              = root@abc.com
        X509v3 extensions:
            X509v3 Basic Constraints: 
                CA:FALSE
            Netscape Comment: 
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier: 
                4C:AE:F0:13:F0:CD:8F:B5:F7:3F:1B:C8:E4:77:91:02:9E:88:6B:5A
            X509v3 Authority Key Identifier: 
                keyid:E3:C1:5E:6D:94:5E:F2:AE:16:67:79:2C:69:B5:B9:10:D9:E0:51:BE
 
Certificate is to be certified until Feb 18 13:45:34 2020 GMT (100 days)
Sign the certificate? [y/n]:y
 
1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated
 
注意：默认要求 countryName（国家），stateOrProvinceName（省），organizationName（公司）三项必须和 CA 一致 

3.4 查看证书中的信息

[root@CentOS7 CA]# openssl x509 -in certs/test.crt -noout -text|issuer|subject|serial|dates

3.5 查看指定编号的证书状态

[root@CentOS7 CA]# openssl ca -status 01
Using configuration from /etc/pki/tls/openssl.cnf
01=Valid (V)

4. 吊销证书

4.1 在客户端获取要吊销的证书的 serial

[root@CentOS7 CA]# openssl x509 -in certs/test.crt -noout -serial -subject
serial=01
subject= /C=CN/ST=beijing/O=abc/OU=IT/CN=hechunping/emailAddress=root@abc.com

4.2 在 CA 上，根据客户提交的 serial 与 subject 信息，对比检验是否与 index.txt 文件中的信息一致

[root@CentOS7 CA]# cat index.txt
V   200218134534Z       01  unknown /C=CN/ST=beijing/O=abc/OU=IT/CN=hechunping/emailAddress=root@abc.com

4.2.1 吊销证书

[root@CentOS7 CA]# openssl ca -revoke newcerts/01.pem 
Using configuration from /etc/pki/tls/openssl.cnf
Revoking Certificate 01.
Data Base Updated

4.2 指定第一个吊销证书的编号，注意：第一次更新证书吊销列表前才需要执行。

[root@CentOS7 CA]# echo 01 > crlnumber

4.3 更新证书吊销列表

[root@CentOS7 CA]# openssl ca -gencrl -out crl.pem
Using configuration from /etc/pki/tls/openssl.cnf

4.4 查看 crl 文件

[root@CentOS7 CA]# openssl crl -in crl.pem -noout -text

将申请下来的证书导出到 windows 中查看

1. 在 windows 上按 ”win+R” 键，然后运行 ”certmgr.msc” 命令。
2. 找到“受信任的根证书颁发机构”右键单击“所有任务”—>“导入”，然后按照向导选择在 Linux 申请下来的证书。
3. 查看证书信息