CA（Certificate Authority）证书颁发机构主要负责证书的颁发、管理以及归档和吊销。证书内包含了拥有证书者的姓名、地址、电子邮件帐号、公钥、证书有效期、发放证书的CA、CA的数字签名等信息。证书主要有三大功能：加密、签名、身份验证。
1.什么是CA认证？
CA认证，即CA认证机构，为电子签名相关各方提供真实性、可靠性验证的行为。
2.什么是CA证书？
证书实际是由证书签证机关（CA）签发的对用户的公钥的认证。
3.CA证书类型？
- 证书颁发机构自签名证书
- 服务器证书
- 用户证书
二. CA服务器部署
1. 部署环境
[root@linux-ca ~]# touch /etc/pki/CA/index.txt #index.txt：索引文件，用于匹配证书编号； [root@linux-ca ~]# echo 01 >/etc/pki/CA/serial #serial：证书序列号文件，只在首次生成证书时赋值。 [root@linux-ca ~]# cat /etc/pki/CA/serial 01
2. 生成密钥
[root@linux-ca private]# (umask 077; openssl genrsa -out /etc/pki/CA/private/cakay.pem 2048)
genrsa：生成私钥；
-out：私钥的存放路径，cakey.pem：为密钥名，与配置文件中保持一致；
2048：密钥长度，默认为1024。
3. 修改配置文件/etc/pki/tls/openssl.cnf
40 [ CA_default ] 41 42 dir = /etc/pki/CA # Where everything is kept 43 certs = $dir/certs # Where the issued certs are kept 44 crl_dir = $dir/crl # Where the issued crl are kept 45 database = $dir/index.txt # database index file. 46 #unique_subject = no # Set to 'no' to allow creation of 47 # several ctificates with same subject. 48 new_certs_dir = $dir/newcerts # default place for new certs. 49 50 certificate = $dir/cacert.pem # The CA certificate 51 serial = $dir/serial # The current serial number 52 crlnumber = $dir/crlnumber # the current crl number 53 # must be commented out to leave a V1 CRL 54 crl = $dir/crl.pem # The current CRL 55 private_key = $dir/private/cakey.pem# The private key 56 RANDFILE = $dir/private/.rand # private random number file 83 # For the CA policy 84 [ policy_match ] 85 countryName = match 86 stateOrProvinceName = match 87 organizationName = match 88 organizationalUnitName = optional 89 commonName = supplied 90 emailAddress = optional 128 [ req_distinguished_name ] 129 countryName = Country Name (2 letter code) 130 countryName_default = US 131 countryName_min = 2 132 countryName_max = 2 133 134 stateOrProvinceName = State or Province Name (full name) 135 stateOrProvinceName_default = California 136 137 localityName = Locality Name (eg, city) 138 localityName_default = Redwood City 139 140 0.organizationName = Organization Name (eg, company) 141 0.organizationName_default = Electronic Arts, Inc. 142 143 # we can do this but it is not needed normally :-) 144 #1.organizationName = Second Organization Name (eg, company) 145 #1.organizationName_default = World Wide Web Pty Ltd 146 147 organizationalUnitName = Organizational Unit Name (eg, section) 148 organizationalUnitName_default = EA Online/pogo.com 149 150 commonName = Common Name (eg, your name or your server's hostname) 151 commonName_max = 64 152 commonName_default = 153 154 emailAddress = Email Address 155 emailAddress_max = 64 156 emailAddress_default =
4. CA 创建自签根证书
[root@linux-ca CA]# openssl req -new -x509 -key /etc/pki/CA/private/cakay.pem -out /etc/pki/CA/cacert.pem -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) [US]: State or Province Name (full name) [California]: Locality Name (eg, city) [Redwood City]: Organization Name (eg, company) [Electronic Arts, Inc.]: Organizational Unit Name (eg, section) [EA Online/pogo.com]: Common Name (eg, your name or your server's hostname) []:cacert Email Address []:vxxxxxxxxxxxxxxxxx
req：生成证书签署请求；
-x509：生成自签署证书；
-days n：证书的有效天数；
-new：新请求；
-key /path/to/keyfile：指定私钥文件；
-out /path/to/somefile：输出文件位置。
三. 客户端申请证书
1. 生成客户端私钥
[root@web ~]# mkdir ssl [root@web ~]# cd ssl/ [root@web ssl]# (umask 077; openssl genrsa -out /root/ssl/web.key 2048) Generating RSA private key, 2048 bit long modulus .......................................+++ .................................................+++ e is 65537 (0x10001)
2. 生成证书请求文件
[root@web ssl]# openssl req -new -key /root/ssl/web.key -out /root/ssl/web.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]:US State or Province Name (full name) []:California Locality Name (eg, city) [Default City]:Redwood City Organization Name (eg, company) [Default Company Ltd]:Electronic Arts, Inc. Organizational Unit Name (eg, section) []:EA Online/pogo.com Common Name (eg, your name or your server's hostname) []:web Email Address []:xxxxxxxxxxx
3. 将生成的申请文件发送到CA颁发服务器
[root@web ssl]# scp web.csr root@10.17.160.241:/etc/pki/CA/csr/
四. CA服务器为客户端颁发证书
1.为客户端颁发证书
[root@linux-ca CA]# openssl ca -in /etc/pki/CA/csr/web.csr -out /etc/pki/CA/certs/web.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: May 15 06:58:48 2019 GMT Not After : May 14 06:58:48 2020 GMT Subject: countryName = US stateOrProvinceName = California organizationName = Electronic Arts, Inc. organizationalUnitName = EA Online/pogo.com commonName = web emailAddress = vli@contractor.ea.com X509v3 extensions: X509v3 Basic Constraints: CA:FALSE Netscape Comment: OpenSSL Generated Certificate X509v3 Subject Key Identifier: 4E:FE:C1:E2:17:92:C6:D1:48:42:70:1F:59:95:FA:9D:49:76:B0:47 X509v3 Authority Key Identifier: keyid:82:81:30:91:40:F8:D2:FD:B4:D5:A8:52:DF:FE:D2:62:12:38:53:7F Certificate is to be certified until May 14 06:58:48 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
2. 将生成的证书发送给申请的客户端
五. 吊销证书
1. 获取证书serial
[root@linux-ca CA]# openssl x509 -in certs/web.crt -noout -serial -subject serial=01 subject= /C=US/ST=California/O=Electronic Arts, Inc./OU=EA Online/pogo.com/CN=web/emailAddress=xxxxxxxxxxxxxx
x509：证书格式；
-in：要吊销的证书；
-noout：不输出额外信息；
-serial：显示序列号；
-subject：显示subject信息。
二） CA验证信息
1、节点提交的serial和subject信息来验证与index.txt文件中的信息是否一致
2、吊销证书
-revoke：删除证书。
查看被吊销的证书列表
3、生成吊销证书的编号（如果是第一次吊销）
4、更新证书吊销列表
-gencrl：生成证书吊销列表；
5、查看crl文件内容
-text：以文本形式显示。
参考： https://www.linuxprobe.com/private-ca.html