man page: Update the --cipher section to reflect recommendations after SWEET32
PATCH 1/1 man page: Update the --cipher section to reflect recommendations after SWEET32
We should no longer make users believe Blowfish is a 'very secure' cipher. Update this section to reflect our recommendations after the SWEET32 announcement.
Trac: #732
--- doc/openvpn.8 | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
doc/openvpn.8 +10 -4
@@ -4110,14 +4110,20 @@ Encrypt data channel packets with cipher algorithm The default is .B BF-CBC, an abbreviation for Blowfish in Cipher Block Chaining mode. -Blowfish has the advantages of being fast, very secure, and allowing key sizes +Blowfish has the advantages of being fast, and allowing key sizes of up to 448 bits. Blowfish is designed to be used in situations where keys are changed infrequently. -For more information on blowfish, see -.I http://www.counterpane.com/blowfish.html +Blowfish was considered very secure for a long time. But recent attacks described +in the SWEET32 discovery makes it very unsuitable. If you depend on Blowfish +today, at least enable more aggressive renegotiation of the tunnel (set +.B \-\-reneg-bytes +to maximum 64MB) and start planning a migration to one of the now recommended AES +ciphers. For more information, see: -To see other ciphers that are available with +.I http://community.openvpn.net/openvpn/wiki/SWEET32 + +To see all ciphers that are available with OpenVPN, use the .B \-\-show\-ciphers option.
Signature · 1 line
1.8.3.1
ACK. Although I thought that Steffan wrote a patch to include that information we, should really have that in our man page.
Also I think the 64 bit cipher warning is not strong enough:
WARNING: this cipher's block size is less than 128 bit (64 bit). Consider using a --cipher with a larger block size.
I think we should reference SWEET32 there too. E.g.:
WARNING: this cipher's block size is less than 128 bit (64 bit) and susceptible to attacks as SWEET32
(http://community.openvpn.net/openvpn/wiki/SWEET32). Consider using a --cipher with a larger block size.
Am 05.10.16 um 14:48 schrieb David Sommerseth:
Quoted 39 lines
We should no longer make users believe Blowfish is a 'very secure' cipher. Update this section to reflect our recommendations after the SWEET32 announcement.
Trac: #732
Signed-off-by David Sommerseth <[email protected]...>--- doc/openvpn.8 | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)doc/openvpn.8 +10
-4@@ -4110,14 +4110,20 @@ Encrypt data channel packets with cipher algorithm The default is .B BF-CBC, an abbreviation for Blowfish in Cipher Block Chaining mode. -Blowfish has the advantages of being fast, very secure, and allowing key sizes +Blowfish has the advantages of being fast, and allowing key sizes of up to 448 bits. Blowfish is designed to be used in situations where keys are changed infrequently. -For more information on blowfish, see -.I http://www.counterpane.com/blowfish.html +Blowfish was considered very secure for a long time. But recent attacks described +in the SWEET32 discovery makes it very unsuitable. If you depend on Blowfish +today, at least enable more aggressive renegotiation of the tunnel (set +.B \-\-reneg-bytes +to maximum 64MB) and start planning a migration to one of the now recommended AES +ciphers. For more information, see: -To see other ciphers that are available with +.I http://community.openvpn.net/openvpn/wiki/SWEET32 + +To see all ciphers that are available with OpenVPN, use the .B \-\-show\-ciphers option.
Gert Doering
NAKHi,
Quoted 3 lines · David Sommerseth
We should no longer make users believe Blowfish is a 'very secure' cipher. Update this section to reflect our recommendations after the SWEET32 announcement.
NAK, as it conflicts with
commit 5a1daf533ae283e258732260c96461e820e61fe6
Author: Steffan Karger <[email protected]...> Date: Sun Sep 11 16:50:31 2016 +0200
Update cipher-related man page text
As reported in trac #732, the man page text for --cipher is no longer accurate. Update the text to represent current knowledge, about NCP and SWEET32.
gert
Signature · 4 lines
USENET is *not* the non-clickable part of WWW!
//www.muc.de/~gert/
Gert Doering - Munich, Germany [email protected]...
fax: +49-89-35655025 [email protected]...