openssl 组件： libcrypto, libssl主要开发者使用； openssl: 多用途命令行工具；
openssl:
从多子命令 分为三类：
标准命令：
消息摘要命令（dgst子命令）
加密命令（enc子命令）
对称加密：
工具：openssl enc
支持的算法：3des,aes,blowfish,towfish
加密命令
enc命令：
实例：
加密~]# openssl enc -e -des3 -a -salt -in fstab -out fstab.ciphertext
解密~]# openssl enc -d -des3 -a -salt -out fstab -in fstab.ciphertext
单向加密：
工具：openssl dgst, md5sum, sha1sum, sha224sum,....
dgst命令：
~]# openssl dgst -md5 fstab
MD5(fstab)= f24b68951add3236d19dff63f0c92206
生成用户密码：
工具： passwd, openssl passwd
~]#openssl passwd -1 -salt 随机数（123456789）
实例：
[root@localhost ~]# openssl passwd -1 -salt $(openssl rand -hex 10)
Password:
$1$9727a8fa$Ir21xFr8gVZJFK1trPohf.
生成随机数：
工具：openssl rand
实例：
[root@localhost ~]# openssl rand -hex 10
8a7f0ab5316d5c0f2aba
[root@localhost ~]# openssl rand -base64 10
G8mVfr06RCHmhQ==
公钥加密：
加密解密：
算法：RSA, ELGamal
工具：openssl rsautl, gpg
数字签名：
算法：RSA, DSA，ELGamal
密钥交换：
算法：DH
生成密钥：
生成私钥： ~]# (umask 077; openssl genrsa -out /tmp/mykey.private 2048)
提出公钥：~]# openssl rsa -in /tmp/mykey.private -pubout
linux系统上的随机数生成器：
/dev/random:仅从熵池返回随机数；随机数用尽，阻塞；
/dev/urandom:从熵池返回随机数；随机数用尽，会利用软件生成伪随机数，非阻塞；
伪随机数不安全；
熵池中随机数的来源；
硬盘IO中断时间间隔；
键盘IO中断时间间隔；
CA:
公共信任的CA,私用CA;
openssl 命令:
配置文件：~]# cat /etc/pki/tls/openssl.cnf
`**构建私有CA:`
在确定配置为CA的服务上生成一个自签证书，并为CA提供所需要的目录及文件即可；
步骤：
1.生成私钥：
~]# (umask 077; openssl genrsa -out /etc/pki/CA/private/cakey.pem 4096)
2.生成自签证书：
-new:生成新证书签署请求；
-x509:生成自签格式证书，专用于创建私有CA时；
-key:生成请求时用到的私有文件路径；
-out:生成的请求文件路径；如果自签操作将直接生成签署过的证书；
-days:证书的有效时长，单位是day;
~]# openssl req -new -x509 -key /etc/pki/CA/private/cakey.pem -out /etc/pki/CA/cacert.pem -days 3655
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) []:guangdong
Locality Name (eg, city) [Default City]:shenzhen
Organization Name (eg, company) [Default Company Ltd]:itxuezhe
Organizational Unit Name (eg, section) []:ops
Common Name (eg, your name or your server's hostname) []:
Email Address []:caadmin@
[root@localhost ~]# ls /etc/pki/CA/
caert.pem certs crl newcerts private
3.为CA提供所需的目录及文件；
~]# mkdir -pv /etc/pki/CA/{certs,crl,newcerts}
~]# touch /etc/pki/CA/{serial,index.txt}
~]# echo 01 > /etc/pki/CA/serial **
要用到证书进行通信的服务器，需要向CA请求签署证书：
步骤：（以httpd主机为例）
1.用到证书的主机生成证书签署请求；
~]# mkdir /etc/httpd/ssl
~]# cd /etc/httpd/ssl
ssl]# (umask 077; openssl genrsa -out httpd.key 2048)
3.2.生成证书签署请求
[root@localhost ssl]# openssl req -new -key httpd.key -out httpd.csr -days 365
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) []:guangdong
Locality Name (eg, city) [Default City]:shenzhen
Organization Name (eg, company) [Default Company Ltd]:itxuezhe
Organizational Unit Name (eg, section) []:ops
Common Name (eg, your name or your server's hostname) []:www.
Email Address []:web@
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
[root@localhost ssl]# ll
总用量 8
-rw-r--r--. 1 root root 1078 12月 10 11:24 httpd.csr
-rw-------. 1 root root 1679 12月 10 11:20 httpd.key
3.将请求通过可靠方式发送给CA主机；
ssl]# scp httpd.csr root@192.168.80.16:/tmp/
root@192.168.80.16's password:
httpd.csr
4.在CA主机上签署证书；
[root@localhost ~]# openssl ca -in /tmp/httpd.csr -out /etc/pki/CA/certs/httpd.crt -days 365
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: Dec 10 03:29:20 2019 GMT
Not After : Dec 9 03:29:20 2020 GMT
Subject:
countryName = CN
stateOrProvinceName = guangdong
organizationName = itxuezhe
organizationalUnitName = ops
commonName = www.
emailAddress = web@
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
OpenSSL Generated Certificate
X509v3 Subject Key Identifier:
D9:B4:2D:FB:4C:5B:EC:8D:5E:90:9F:1B:C6:61:65:0C:FB:94:59:8C
X509v3 Authority Key Identifier:
keyid:44:C1:C1:A7:B5:5F:15:15:06:8B:3B:7C:15:CB:5E:B4:A6:19:FD:5E
Certificate is to be certified until Dec 9 03:29:20 2020 GMT (365 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
证书签署成功
~]# cd /etc/pki/CA/
CA]# cat index.txt
V 201209032920Z 01 unknown/C=CN/ST=guangdong/O=itxuezhe/OU=www./CN=www./emailAddress=web@
将签署成功的证书发送给申请证书的主机
CA]# scp certs/httpd.crt root@192.168.80.17:/etc/httpd/ssl/
The authenticity of host '192.168.80.17 (192.168.80.17)' can't be established.
ECDSA key fingerprint is SHA256:iyMPO9k4t5oUNnOcDCOkJTLBLOSBKKPRuR9AugKmftM.
ECDSA key fingerprint is MD5:73:2e:7e:37:b4:48:b9:45:3e:96:f1:ec:6a:9a:59:fd.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.80.17' (ECDSA) to the list of known hosts.
root@192.168.80.17's password:
httpd.crt
查看证书中的信息：
[root@localhost ssl]# openssl x509 -in httpd.crt -noout -serial -subject
serial=01
subject= /C=CN/ST=guangdong/O=itxuezhe/OU=www./CN=www./emailAddress=web@
吊销证书：
步骤：
1.客户端获取要吊销的证书的serial (在使用证书的主机执行)；
[root@localhost ssl]# openssl x509 -in /etc/pki/CA/certs/httpd.crt -noout -seral -subject
主机吊销证书
先根据客户端提交的serial和subject信息，对比其与本机数据库index.txt中存储的是否一致；
吊销：
[root@localhost CA]# openssl ca -revoke /etc/pki/CA/newcerts/SERIAL.pem
[root@localhost CA]# openssl ca -revoke /etc/pki/CA/newcerts/01.pem
其中的SERIAL要换成证书真正的序列号;
3.生成吊销证书的吊销编号（第一次吊销证书时执行）
CA]# echo 01 > /etc/pki/CA/crlnumber
4.更新证书吊销列表
CA]# openssl ca -gencrl -out thisca.crl
查看crl文件：
]# openssl crl -in /PATH/FROM/CRL_FILE.crl -noout -text
