similar to: upgrade 2.2 to 2.3, diffie-hellman, ssl_min_protocol

Thanks Joseph, Aki, but something missing from upgrade document, where does the dh param file go? I located ssl-parameters.dat so I will put it there. Quoting Joseph Tam <jtam.home at gmail.com>: > On Fri, 22 Jun 2018, Joseph Tam wrote: > >> However, recent advances make this condition obsolete [*] and not >> really safer, so a much faster way to generate a DH key is

On Fri, 22 Jun 2018, Aki Tuomi wrote: >> Do I need to make a fresh dh.pem? The upgrade doc tells how to convert >> ssl-parameters.dat but how to make a new one? > > ... or you can make a fresh one using openssl > gendh 4096 > dh.pem This also works openssl dhparam -out dh.pem 4096 > Note that this will require quite a lot of entropy, so you should > probably

> On 22 June 2018 at 10:18 tai74 at vfemail.net wrote: > > > > hi sorry if question was asked already. Was reading > https://wiki2.dovecot.org/Upgrading/2.3 > > first I'm confused on diffie hellman parameters file. I never set up > ssl-parameters.dat before (should i have? do I have one that was > automatically made for me by dovecot?) > > Do I need

On Fri, 22 Jun 2018, Joseph Tam wrote: > However, recent advances make this condition obsolete [*] and not > really safer, so a much faster way to generate a DH key is > > openssl dhparam -dsaparam -out dh.pem 4096 > > DH generation is a one time operation, so if you're paranoid and you've > got time to burn, go ahead and generate the "safe" DH key. >

> On 19 August 2018 at 20:55 Aki Tuomi <aki.tuomi at dovecot.fi> wrote: > > > > > On 19 August 2018 at 19:38 Kai Schaetzl <maillists at conactive.com> wrote: > > > > > > Aki Tuomi wrote on Sun, 19 Aug 2018 18:21:31 +0300: > > > > > Just generate new parameters on some machine with good entropy source. > > > > So, if

A few questions regarding the OpenSSH support for the Diffie Hellman key exchange algorithms: (1) Are the diffie-hellman-group-exchange-sha256", "diffie-hellman-group-exchange-sha1" , "diffie-hellman-group14-sha1" "diffie-hellman-group1-sha1" (as defined in RFCs 4253 and RFC 4419) the complete list of key exchange algorithms supported by OpenSSH? (2) Is there a

I'm not sure if collision resistance is required for DH key derivation, but generally, SHA-1 is on its way out. If it's possible (if there's not a very large percentage of servers that do not support anything newer), it should be disabled.

That doesn't seem to be the case. See https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r4.pdf (5.6.1 Comparable Algorithm Strengths) On Fri, Feb 15, 2019 at 8:28 AM Darren Tucker <dtucker at dtucker.net> wrote: > > On Fri, 15 Feb 2019 at 16:00, Yegor Ievlev <koops1997 at gmail.com> wrote: > > I don't think there is any point to generate so

e.g. can we make it throw warnings etc. rsa-sha2-256 and rsa-sha2-512 are fine, they use PSS. On Sun, Jan 20, 2019 at 1:55 AM Yegor Ievlev <koops1997 at gmail.com> wrote: > > Also can we do anything with ssh-rsa? It uses both SHA-1 and > deprecated PKCS#1 padding. If it's used to sign certificates, there's > no additional protection of SHA-2 hashing before SHA-1

I?m setting up Dovecot using Homebrew on a new server and am getting this when I try to login via IMAP: Nov 13 14:13:35 auth: Debug: auth client connected (pid=30719) Nov 13 14:13:35 imap-login: Info: Aborted login (no auth attempts in 0 secs): user=<>, rip=::1, lip=::1, secured, session=<gM0HNIN6HtoAAAAAAAAAAAAAAAAAAAAB> Nov 13 14:18:33 auth: Debug: Loading modules from directory:

Currently, dovecot generates two primes for Diffie-Hellman key exchanges: a 512-bit one and a 1024-bit one. In light of recent events, I think it would be wise to add support for 2048-bit primes as well, or even better, add a configuration option that lets the user select a file (or files) containing the DH parameters In recent years, there has been increased interest in DH especially in its

Hello, On Sun, Sep 22, 2024 at 10:15?AM Kurt Fitzner via openssh-unix-dev <openssh-unix-dev at mindrot.org> wrote: > > I would like to advocate for: > > - Change behaviour of the server to allow server operators to set the > minimum modulus group size allowable for a connection using > diffie-hellman-group-exchange-sha256 > Whether this is by having the server refuse

Hello all, I have recently had cause to dig a little into the specifics of how diffie-hellman-group-exchange-sha256 group sizes work. The belief in the wild, perpetuated by multiple sources of logjam mediation papers and also Andras Stribnik's very influential piece "Secure Secure Shell", is that server operators can force the use of a minimum group size by removing moduli

I have been reading up on TLS and Dovecot and came across this URL: https://www.weakdh.org/sysadmin.html which recommended these settings for Dovecot. I would like to know if they are correct? Some much documentation on the web is pure garbage. Dovecot These changes should be made in /etc/dovecot.conf Cipher Suites

I referred to the fact that there is no value for 4096-bit groups at all. For higher strengths than 128 bits one should probably not use non-EC crypto at all, as the document suggests. On Fri, Feb 15, 2019 at 9:19 AM Darren Tucker <dtucker at dtucker.net> wrote: > > On Fri, 15 Feb 2019 at 16:45, Yegor Ievlev <koops1997 at gmail.com> wrote: > > That doesn't seem to be

https://bugzilla.mindrot.org/show_bug.cgi?id=2515 Bug ID: 2515 Summary: Implement diffie-hellman-group{14,15,16)-sha256 Product: Portable OpenSSH Version: -current Hardware: All OS: All Status: ASSIGNED Severity: enhancement Priority: P3 Component: ssh Assignee: dtucker at

On Fri, 2019-02-15 at 15:57 +1100, Darren Tucker wrote: > That was the original intent (and it's mentioned in RFC4419) however > each moduli file we ship (70-80 instances of 6 sizes) takes about 1 > cpu-month to generate on a lowish-power x86-64 machine. Most of it > is > parallelizable, but even then it'd likely take a few hours to > generate > one of each size. I

Can we disable diffie-hellman-group14-sha1 too? On Thu, Feb 14, 2019 at 10:23 PM Mark D. Baushke <mdb at juniper.net> wrote: > > Hi John, > > The short answer is YES. > > Jon DeVree <nuxi at vault24.org> writes: > > > I ask because the removal of diffie-hellman-group-exchange-sha1 happened > > accidently in 7.8 due to a mistake in a change to

https://bugzilla.mindrot.org/show_bug.cgi?id=2291 Bug ID: 2291 Summary: ssh -Q kex lists diffie-hellman-group1-sha1 twice Product: Portable OpenSSH Version: 6.7p1 Hardware: Other OS: Linux Status: NEW Severity: minor Priority: P5 Component: sftp-server Assignee:

I ask because the removal of diffie-hellman-group-exchange-sha1 happened accidently in 7.8 due to a mistake in a change to readconf.c. I noticed this and filed a bug about it along with a patch to fix readconf.c to use KEX_CLIENT_* like it used to: https://github.com/openssh/openssh-portable/commit/1b9dd4aa https://bugzilla.mindrot.org/show_bug.cgi?id=2967 Its clear the removal was unintentional