CRIPTOGRAFIA - FESP

Leaving everything commented (as is), is identical as uncommenting the
following line:
cipher BF-CBC
# Blowfish (default)
The result is the same.
But you may wish to use another type of encryption such as this one:
cipher AES-256-CBC
With the above line, you will the have 256-bit version of AES (Advanced
Encryption Standard).
When using another encryption type then the default cipher BF-CBC, you will
need to set the same on the client side.
To obtain a list of the different types of encryption supported by openvpn, type
the following command:
openvpn --show-ciphers
The displayed result will look like this:
The following ciphers and cipher modes are available
for use with OpenVPN. Each cipher shown below may be
used as a parameter to the --cipher option. The default
key size is shown as well as whether or not it can be
changed with the --keysize directive. Using a CBC mode
is recommended.
DES-CBC 64 bit default key (fixed)
IDEA-CBC 128 bit default key (fixed)
RC2-CBC 128 bit default key (variable)
DES-EDE-CBC 128 bit default key (fixed)
DES-EDE3-CBC 192 bit default key (fixed)
DESX-CBC 192 bit default key (fixed)
BF-CBC 128 bit default key (variable)
RC2-40-CBC 40 bit default key (variable)
CAST5-CBC 128 bit default key (variable)
RC5-CBC 128 bit default key (variable)
RC2-64-CBC 64 bit default key (variable)
AES-128-CBC 128 bit default key (fixed)
AES-192-CBC 192 bit default key (fixed)
AES-256-CBC 256 bit default key (fixed)
if you want to change the default keysize chose a cipher mode with variable key
size from the list above, and do as the following example in
/etc/openvpn.server.conf:
cipher BF-CBC
keysize 512
But don't forget to set the same in the client configuration file.