linux下使用openssl生成 csr crt CA證書

本文主要借鑑和引用了下面2個地址的內容，然後在自己的機器上進行了測試和執行，並做了如下記錄。

ref:

http://blog.chinaunix.net/uid-26760055-id-3128132.html

http://www.111cn.net/sys/linux/61591.htm

創建測試目錄

mkdir /tmp/create_key/ca

cd /tmp/create_key/

證書文件生成:
一.服務器端
1.生成服務器端    私鑰(key文件);
openssl genrsa -des3 -out server.key 1024
運行時會提示輸入密碼,此密碼用於加密key文件(參數des3是加密算法,也可以選用其他安全的算法),以後每當需讀取此文件(通過openssl提供的命令或API)都需輸入口令.如果不要口令,則去除口令:openssl rsa -in server.key -out server.key

2.生成服務器端    證書籤名請求文件(csr文件);
openssl req -new -key server.key -out server.csr
生成Certificate Signing Request（CSR）,生成的csr文件交給CA簽名後形成服務端自己的證書.屏幕上將有提示,依照其 提示一步一步輸入要求的個人信息即可(如:Country,province,city,company等).

二.客戶端
1.生成客戶端     私鑰(key文件);
openssl genrsa -des3 -out client.key 1024

2.生成客戶端    證書籤名請求文件(csr文件);
openssl req -new -key client.key -out client.csr

cd  /tmp/create_key/ca
三.生成CA證書文件
#server.csr與client.csr文件必須有CA的簽名纔可形成證書.
1.首先生成CA的key文件:
openssl genrsa -des3 -out ca.key 1024
2.生成CA自簽名證書:
openssl req -new -x509 -key ca.key -out ca.crt 
可以加證書過期時間選項 "-days 365".

四.利用CA證書進行簽名

openssl ca -in ../server.csr -out ../server.crt -cert ca.crt -keyfile ca.key 

openssl ca -in ../client.csr -out ../client.crt -cert ca.crt -keyfile ca.key 

這兩條執行的時候因爲沒有指定openssl.cnf 會報錯，不過沒關係，我們用默認的 /etc/pki/tls/openssl.cnf 就可以。

不過用默認的時候需要先執行下面兩行：

touch /etc/pki/CA/index.txt 

echo 00 > /etc/pki/CA/serial    

下面有錯誤案例分析

#############################################################

根據server.csr 通過CA的ca.crt   ca.key  生成server.crt文件

openssl ca -in ../server.csr -out ../server.crt -cert ca.crt -keyfile ca.key 
Using configuration from /etc/pki/tls/openssl.cnf 
Enter pass phrase for ca.key: 
/etc/pki/CA/index.txt: No such file or directory 
unable to open '/etc/pki/CA/index.txt' 
140423531685704:error:02001002:system library:fopen:No such file or directory:bss_file.c:355:fopen('/etc/pki/CA/index.txt','r') 
140423531685704:error:20074002:BIO routines:FILE_CTRL:system lib:bss_file.c:357: 
[root@monitor ca]# touch /etc/pki/CA/index.txt             #創建index文件，因爲不存在
[root@monitor ca]# openssl ca -in ../server.csr -out ../server.crt -cert ca.crt -keyfile ca.key 
Using configuration from /etc/pki/tls/openssl.cnf 
Enter pass phrase for ca.key: 
/etc/pki/CA/serial: No such file or directory 
error while loading serial number 
139949960836936:error:02001002:system library:fopen:No such file or directory:bss_file.c:355:fopen('/etc/pki/CA/serial','r') 
139949960836936:error:20074002:BIO routines:FILE_CTRL:system lib:bss_file.c:357: 
[root@monitor ca]# echo 00 > /etc/pki/CA/serial                 #創建serial號文件
[root@monitor ca]# openssl ca -in ../server.csr -out ../server.crt -cert ca.crt -keyfile ca.key 
Using configuration from /etc/pki/tls/openssl.cnf 
Enter pass phrase for ca.key: 
Check that the request matches the signature 
Signature ok 
The organizationName field needed to be the same in the 
CA certificate (homelink-ca) and the request (homelink)                

#此處報錯是因爲創建CA的ca.crt 時候 和創建server的server.csr時候    

#Organization Name (eg, company) [Default Company Ltd]:homelink-ca  和

#Organization Name (eg, company) [Default Company Ltd]:homelink  

#配置的不再一個域，所以不行，下面重建ca.crt

[root@monitor ca]# openssl req -new -x509 -key ca.key -out ca.crt 
Enter pass phrase for ca.key: 
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]:homelink 
Organizational Unit Name (eg, section) []:homelink-lft 
Common Name (eg, your name or your server's hostname) []:lft 
Email Address []: 
[root@monitor ca]# ls -lrt 
total 8 
-rw-r--r-- 1 root root 963 May 22 14:39 ca.key 
-rw-r--r-- 1 root root 944 May 22 16:16 ca.crt 

#重新創建ca.crt後，重新執行，生成成功
[root@monitor ca]# openssl ca -in ../server.csr -out ../server.crt -cert ca.crt -keyfile ca.key 
Using configuration from /etc/pki/tls/openssl.cnf 
Enter pass phrase for ca.key: 
Check that the request matches the signature 
Signature ok 
Certificate Details: 
Serial Number: 0 (0x0) 
Validity 
Not Before: May 22 08:16:25 2015 GMT 
Not After : May 21 08:16:25 2016 GMT 
Subject: 
countryName = CN 
stateOrProvinceName = bj 
organizationName = homelink 
organizationalUnitName = homelink-lft 
commonName = lft 
X509v3 extensions: 
X509v3 Basic Constraints: 
CA:FALSE 
Netscape Comment: 
OpenSSL Generated Certificate 
X509v3 Subject Key Identifier: 
00:2C:34:0A:73:5C:1A:E6:39:48:28:6F:8F:02:F6:BC:58:6F:25:55 
X509v3 Authority Key Identifier: 
keyid:83:70:9D:4E:3F:39:01:3E:7A:CE:B9:2B:0E:1A:FB:00:2A:C3:11:D9 

Certificate is to be certified until May 21 08:16:25 2016 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 
[root@monitor ca]# ls -lrt 
total 8 
-rw-r--r-- 1 root root 963 May 22 14:39 ca.key 
-rw-r--r-- 1 root root 944 May 22 16:16 ca.crt 
[root@monitor ca]# ls -lrt .. 
total 28 
-rw-r--r-- 1 root root 963 May 22 13:51 server.key 
-rw-r--r-- 1 root root 672 May 22 13:52 server.csr 
-rw-r--r-- 1 root root 963 May 22 14:36 client.key 
-rw-r--r-- 1 root root 672 May 22 14:37 client.csr 
drwxr-xr-x 2 root root 4096 May 22 14:40 ca 
-rw-r--r-- 1 root root 238 May 22 15:07 readme.txt 
-rw-r--r-- 1 root root 3036 May 22 16:16 server.crt

#然後生成客戶端的client.crt 文件

openssl ca -in ../client.csr -out ../client.crt -cert ca.crt -keyfile ca.key