Merge remote-tracking branch 'origin/master'

Author: tiamo

docs/certificate.md

@@ -2,13 +2,25 @@
 Generate a couple private and public key: 
 
 ```bash
-openssl req -newkey rsa:2048 -nodes -keyout privkey.pem -x509 -days 365 -out public.pem
+openssl req -newkey rsa:2048 -sha1 -nodes -keyout private.pem -x509 -days 1095 -out server.pub -subj "/C=US/ST=MyDept/L=m=MyCity/O=myCompany/OU=IT/CN=mydomain.com"
+```
+
+Extract a pkcs7 cert file:
+
+```bash
+openssl crl2pkcs7 -nocrl -certfile server.pub -out cert.p7b
+```
+
+Extract a smine cert file from pkcs7:
+
+```bash
+openssl pkcs7 -in cert.p7b -out smime-cert.pem -print_certs
 ```
 
 Merge them into a p12 file:
 
 ```bash
-openssl pkcs12 -inkey privkey.pem -in public.pem -export -out server.p12
+openssl pkcs12 -inkey cert.p7b -in smime-cert.pem -inkey private.pem -in server.pub -export -out server.p12 -nodes -passout pass:
 ```
 
 Check your p12 file: