Question on ciphers
Posted: Tue Aug 13, 2013 7:37 am
I have a couple of questions regarding ciphers. Too many results appear in the search so I am hoping someone can either answer this, or point me to a relevant thread.
First, I have openvpn working just fine, between the website and the forums, I got what I needed, so that's great.
I've got the following in my config file:
What is the difference between all of the ciphers and tls-ciphers? Is there some sort of general guideline? For instance, the difference between CBC and OFB, etc.?
First, I have openvpn working just fine, between the website and the forums, I got what I needed, so that's great.
I've got the following in my config file:
Code: Select all
cipher AES-256-CBC
tls-cipher DHE-RSA-AES256-SHACode: Select all
openvpn --show-tls
Available TLS Ciphers,
listed in order of preference:
DHE-RSA-AES256-SHA
DHE-DSS-AES256-SHA
AES256-SHA
EDH-RSA-DES-CBC3-SHA
EDH-DSS-DES-CBC3-SHA
DES-CBC3-SHA
DHE-RSA-AES128-SHA
DHE-DSS-AES128-SHA
AES128-SHA
RC4-SHA
RC4-MD5
EDH-RSA-DES-CBC-SHA
EDH-DSS-DES-CBC-SHA
DES-CBC-SHA
EXP-EDH-RSA-DES-CBC-SHA
EXP-EDH-DSS-DES-CBC-SHA
EXP-DES-CBC-SHA
EXP-RC2-CBC-MD5
EXP-RC4-MD5
openvpn --show-ciphers
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-CFB 64 bit default key (fixed)
DES-CBC 64 bit default key (fixed)
RC2-CBC 128 bit default key (variable)
RC2-CFB 128 bit default key (variable)
RC2-OFB 128 bit default key (variable)
DES-EDE-CBC 128 bit default key (fixed)
DES-EDE3-CBC 192 bit default key (fixed)
DES-OFB 64 bit default key (fixed)
DES-EDE-CFB 128 bit default key (fixed)
DES-EDE3-CFB 192 bit default key (fixed)
DES-EDE-OFB 128 bit default key (fixed)
DES-EDE3-OFB 192 bit default key (fixed)
DESX-CBC 192 bit default key (fixed)
BF-CBC 128 bit default key (variable)
BF-CFB 128 bit default key (variable)
BF-OFB 128 bit default key (variable)
RC2-40-CBC 40 bit default key (variable)
CAST5-CBC 128 bit default key (variable)
CAST5-CFB 128 bit default key (variable)
CAST5-OFB 128 bit default key (variable)
RC2-64-CBC 64 bit default key (variable)
AES-128-CBC 128 bit default key (fixed)
AES-128-OFB 128 bit default key (fixed)
AES-128-CFB 128 bit default key (fixed)
AES-192-CBC 192 bit default key (fixed)
AES-192-OFB 192 bit default key (fixed)
AES-192-CFB 192 bit default key (fixed)
AES-256-CBC 256 bit default key (fixed)
AES-256-OFB 256 bit default key (fixed)
AES-256-CFB 256 bit default key (fixed)
AES-128-CFB1 128 bit default key (fixed)
AES-192-CFB1 192 bit default key (fixed)
AES-256-CFB1 256 bit default key (fixed)
AES-128-CFB8 128 bit default key (fixed)
AES-192-CFB8 192 bit default key (fixed)
AES-256-CFB8 256 bit default key (fixed)
DES-CFB1 64 bit default key (fixed)
DES-CFB8 64 bit default key (fixed)
DES-EDE3-CFB1 192 bit default key (fixed)
DES-EDE3-CFB8 192 bit default key (fixed)
openvpn --show-digests
The following message digests are available for use with
OpenVPN. A message digest is used in conjunction with
the HMAC function, to authenticate received packets.
You can specify a message digest as parameter to
the --auth option.
MD5 128 bit digest size
RSA-MD5 128 bit digest size
SHA 160 bit digest size
RSA-SHA 160 bit digest size
SHA1 160 bit digest size
RSA-SHA1 160 bit digest size
DSA-SHA 160 bit digest size
DSA-SHA1-old 160 bit digest size
DSA-SHA1 160 bit digest size
RSA-SHA1-2 160 bit digest size
DSA 160 bit digest size
RIPEMD160 160 bit digest size
RSA-RIPEMD160 160 bit digest size
MD4 128 bit digest size
RSA-MD4 128 bit digest size
ecdsa-with-SHA1 160 bit digest size
RSA-SHA256 256 bit digest size
RSA-SHA384 384 bit digest size
RSA-SHA512 512 bit digest size
RSA-SHA224 224 bit digest size
SHA256 256 bit digest size
SHA384 384 bit digest size
SHA512 512 bit digest size
SHA224 224 bit digest size