使用OpenSSL建立CA和申請證書

OpenSSL簡介

OpenSSL是一種加密工具套件，可實現安全套接字層（SSL v2 / v3）和傳輸層安全性（TLS v1）網絡協議以及它們所需的相關加密標準。

openssl命令行工具用於從shell程序使用OpenSSL加密庫的各類加密功能。 它能夠用於：

• 建立和管理私鑰，公鑰和參數
• 公鑰加密操做
• 建立X.509證書，CSR和CRL
• 消息摘要的計算
• 使用密碼進行加密和解密
• SSL / TLS客戶端和服務器測試
• 處理S / MIME簽名或加密的郵件
• 時間戳記請求，生成和驗證

openssl配置文件及三種策略

配置文件
/etc/pki/tls/openssl.cnf

三種策略
match（匹配）：要求申請填寫的信息跟CA設置信息必須一致
optional（可選）：無關緊要，跟CA設置信息可不一致
supplied（提供）：必須填寫這項申請信息

建立私有CA和申請、頒發證書文件（如下操做都是在一臺機器上執行）

1.建立所須要的文件

[root@CentOS7 ~]# cd /etc/pki/CA/
[root@CentOS7 CA]# touch index.txt  生成證書索引數據庫文件
[root@CentOS7 CA]# echo 01 > serial 指定第一個頒發證書的序列號

2.CA自簽證書

2.1生成私鑰

[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生成自簽名證書

[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

選項說明：
-new：生成新證書籤署請求
-x509：專用於CA生成自簽證書
-key：生成請求時用到的私鑰文件
-days n：證書的有效期限
-out /PATH/TO/SOMECERTFILE: 證書的保存路徑

3.頒發證書

3.1在須要使用證書的主機生成證書請求（本實驗是在本機）

3.1.1生成私鑰

[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生成證書申請文件

[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將證書申請文件傳輸給CA（兩臺不一樣的主機能夠使用scp命令傳輸）

3.3CA簽署證書，並將證書頒發給請求者

[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：默認要求 countryName（國家），stateOrProvinceName（省），organizationName（公司）三項必須和CA一致

3.4查看證書中的信息

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

3.5查看指定編號的證書狀態

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

4.吊銷證書

4.1在客戶端獲取要吊銷的證書的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，根據客戶提交的serial與subject信息，對比檢驗是否與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吊銷證書

[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指定第一個吊銷證書的編號，注意：第一次更新證書吊銷列表前才須要執行。

[root@CentOS7 CA]# echo 01 > crlnumber

4.3更新證書吊銷列表

[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

將申請下來的證書導出到windows中查看

1.在windows上按"win+R"鍵，而後運行"certmgr.msc"命令。
2.找到「受信任的根證書頒發機構」右鍵單擊「全部任務」--->「導入」，而後按照嚮導選擇在Linux申請下來的證書。
3.查看證書信息