自建 ca 及使用 ca 颁发证书

创建CA：

一、安装openssl

[root@localhost ~]# yum install -y openssl

二、创建CA的相关文件及目录

mkdir /opt/root_ca &&
　　cd root_ca &&
　　mkdir newcerts private crl &&
　　touch index.txt &&
　　touch serial &&
　　echo 01 >serial &&

说明：　　
　　#newcerts目录用于存放CA签署（颁发）过的数字证书（证书备份目录）。 
　　#private目录用于存放CA的私钥。 
　　#文件serial和index.txt分别用于存放下一个证书的序列号和证书信息数据库。 
　　#文件serial填写第一个证书序列号（如10000001），之后每前一张证书，序列号自动加1。

三、修改openssl配置文件

vim /etc/pki/tls/openssl.cnf

[ CA_default ]
dir = /opt/root_ca

[ policy_match ]
countryName = match
stateOrProvinceName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

说明：
　　match 　　表示严格校验国家名称
　　optional 表示可选
　　这个“匹配”指的是在颁发证书的时候，检查请求中的信息是否和根证书中所对应的信息匹配；
　　加粗的部分为需要修改的配置，具体配置根据实际情况修改

四、生成CA私钥

[root@localhost root_ca] openssl genrsa -out private/ca.key
Generating RSA private key, 2048 bit long modulus
..................+++
...............................+++
e is 65537 (0x10001)

五、使用私钥生成CA请求信息

[root@localhost root_ca]# openssl req -new -key private/ca.key -out ca.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) []:BJ
Locality Name (eg, city) [Default City]:BJ
Organization Name (eg, company) [Default Company Ltd]:ESTREND
Organizational Unit Name (eg, section) []:IT
Common Name (eg, your name or your server's hostname) []:www.estrend.com
Email Address []:admin@estrend.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

六、使用CA私钥和证书请求，生成CA根证书

[root@localhost root_ca]# openssl x509 -req -days 3650 -in ca.csr -signkey private/ca.key -out ca.crt
Signature ok
subject=/C=CN/ST=BJ/L=BJ/O=ESTREND/OU=IT/CN=www.estrend.com/emailAddress=admin@estrend.com
Getting Private key

颁发证书：

一、生成私钥

[root@localhost s1]# openssl genrsa -out server.key    
Generating RSA private key, 2048 bit long modulus
..................+++
...............................+++
e is 65537 (0x10001)

二、生成请求

[root@localhost server]# openssl req -new -key server.key -out server.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) []:BJ
Locality Name (eg, city) [Default City]:BJ
Organization Name (eg, company) [Default Company Ltd]:ESTREND
Organizational Unit Name (eg, section) []:IT
Common Name (eg, your name or your server's hostname) []:www.123.com
Email Address []:admin@123.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

三、颁发证书

[root@localhost server]# openssl ca -in server.csr -cert /opt/root_ca/ca.crt -keyfile /opt/root_ca/private/ca.key -out server.crt -days 3650
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: May  9 07:50:01 2019 GMT
            Not After : May  6 07:50:01 2029 GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = BJ
            organizationName          = ESTREND
            organizationalUnitName    = IT
            commonName                = www.123.com
            emailAddress              = admin@123.com
        X509v3 extensions:
            X509v3 Basic Constraints: 
                CA:FALSE
            Netscape Comment: 
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier: 
                EA:DB:4B:E6:18:C6:23:15:33:86:EA:C2:7B:D5:60:85:FB:45:41:D4
            X509v3 Authority Key Identifier: 
                DirName:/C=CN/ST=BJ/L=BJ/O=ESTREND/OU=IT/CN=www.estrend.com/emailAddress=admin@estrend.com
                serial:B8:7C:0A:A8:8D:2E:AF:23

Certificate is to be certified until May  6 07:50:01 2029 GMT (3650 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