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Update cipher-related man page text

PATCH In review Steffan Karger 2 participants 2 messages Sep 11, 2016 – Oct 4, 2016

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PATCH 1/1 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.

This does not hint at changing the default cipher, because we did not make a decision on that yet. If we do change the default cipher, we'll have to update the text to reflect that.

---
 doc/openvpn.8 | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)
doc/openvpn.8 +3 -11
index d9bb77c..fd23f8b 100644
@@ -3910,22 +3910,14 @@ 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
-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
+Using BF-CBC is no longer recommended, because of it's 64-bit block size.  This
+small block size allows attacks based on collisions, as demonstrated by SWEET32.
 
-To see other ciphers that are available with
-OpenVPN, use the
+To see other ciphers that are available with OpenVPN, use the
 .B \-\-show\-ciphers
 option.
 
-OpenVPN supports the CBC, CFB, and OFB cipher modes,
-however CBC is recommended and CFB and OFB should
-be considered advanced modes.
-
 Set
 .B alg=none
 to disable encryption.
Signature · 1 line
2.7.4
#1 lore raw

ACK.

Your patch has been applied to the release/2.3 branch.

commit db6cdf90b1c0696b93a551aab7c9c9925c6774df

Author: Steffan Karger
Date:   Sun Sep 11 16:51:17 2016 +0200
     Update cipher-related man page text

     Signed-off-by: Steffan Karger <[email protected]...>
     Acked-by: Gert Doering <[email protected]...>
     Message-Id: <[email protected]...>
     URL: https://www.mail-archive.com/[email protected]/msg12440.html
     Signed-off-by: Gert Doering <[email protected]...>

--
kind regards,

Gert Doering