El primer paso que debemos dar es crear un certificado firmado por nosotros mismos. Será con este certificado que en el futuro nosotros podremos firmar los certificados que nos sean solicitados. Utilizaremos el script CA.pl localizado en /usr/local/ssl/misc para poder concentrarnos más en el procedimiento que en los detalles sintácticos.
El primer paso es crear la estructura necesaria para levantar sobre esta nuestra autoridad certificadora:
$ /usr/local/ssl/misc/CA.pl -newca
CA certificate filename (or enter to create)
Dejamos en blanco
Making CA certificate ...
Using configuration from /usr/local/ssl/openssl.cnf
Generating a 1024 bit RSA private key
...........................++++++
................................++++++
writing new private key to './demoCA/private/cakey.pem'
Enter PEM pass phrase: ejemplo
Verifying password - Enter PEM pass phrase: ejemplo
---
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) [AU]:MX
State or Province Name (full name) [Some-State]:Distrito Federal
Locality Name (eg, city) []:Mexico
Organization Name (eg, company) [Internet Widgits Pty Ltd]:UNAM
Organizational Unit Name (eg, section) []:DGSCA
Common Name (eg, YOUR name) []:Area de Seguridad en Computo
Email Address []:asc@asc.unam.mx
La contraseña que dimos aquí arriba es de vital importancia - la utilizaremos siempre que queramos firmar un certificado. Sin esta, OpenSSL se quejará y abortará la operación.
Quedamos ahora con un directorio demoCA en el cual trabajaremos con nuestra autoridad certificadora. Ahora generamos una petición de certificado:
$ /usr/local/ssl/misc/CA.pl -newreq
Using configuration from /usr/local/ssl/openssl.cnf
Generating a 1024 bit RSA private key
.++++++
.......................++++++
writing new private key to 'newreq.pem'
Enter PEM pass phrase: otroejemplo
Verifying password - Enter PEM pass phrase: otroejemplo
---
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) [AU]:MX
State or Province Name (full name) [Some-State]:Distrito Federal
Locality Name (eg, city) []:Mexico
Organization Name (eg, company) [Internet Widgits Pty Ltd]:UNAM
Organizational Unit Name (eg, section) []:DGSCA
Common Name (eg, YOUR name) []:Area de Seguridad en Computo
Email Address []:asc@asc.unam.mx
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:secreta
An optional company name []:UNAM
Request (and private key) is in newreq.pem
Queda entonces hecha la petición de certificado, así como nuestra llave privada, en el archivo newreq.pem - El siguiente paso es firmarlo:
$ /usr/local/ssl/misc/CA.pl -sign
Using configuration from /usr/local/ssl/openssl.cnf
Enter PEM pass phrase: ejemplo
Check that the request matches the signature
Signature ok
The Subjects Distinguished Name is as follows
countryName :PRINTABLE:'MX'
stateOrProvinceName :PRINTABLE:'Distrito Federal'
localityName :PRINTABLE:'Mexico'
organizationName :PRINTABLE:'UNAM'
organizationalUnitName:PRINTABLE:'DGSCA'
commonName :PRINTABLE:'Area de Seguridad en Computo'
emailAddress :IA5STRING:'asc@asc.unam.mx'
Certificate is to be certified until Jul 3 19:42:25 2001 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
Signed certificate is in newcert.pem
Por último, toca poner nuestro certificado firmado por nosotros mismos en donde OpenSSL espera encontrarlo - en el directorio especificado en /usr/local/ssl/openssl.cnf.
$ su root
Password:
# cp newcert.pem /usr/local/ssl/private/
# cp demoCA/private/cakey.pem /usr/local/ssl/private/