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I know that is possible to convert .ppk under puttygen in Windows, but how to do that on Linux? Is this possible ?

slhck
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marioosh
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4 Answers4

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Do it with Putty.

  • Linux: with your package manager, install PuTTY (or the more minimal PuTTY-tools):
  • Ubuntu: sudo apt-get install putty-tools
  • Debian-like: apt-get install putty-tools
  • RPM based: dnf install putty or yum install putty
  • Gentoo: emerge putty
  • Archlinux: sudo pacman -S putty
  • etc.
  • OS X: Install Homebrew, then run brew install putty

Place your keys in some directory, e.g. your home folder. Now convert the PPK keys to SSH keypairs:cache search

To generate the private key:

cd ~
puttygen id_dsa.ppk -O private-openssh -o id_dsa

and to generate the public key:

puttygen id_dsa.ppk -O public-openssh -o id_dsa.pub

Move these keys to ~/.ssh and make sure the permissions are set to private for your private key:

mkdir -p ~/.ssh
mv -i ~/id_dsa* ~/.ssh
chmod 600 ~/.ssh/id_dsa
chmod 666 ~/.ssh/id_dsa.pub

If you have already tried to perform a 'git clone' operation you might need to do this also

chmod 666 ~/.ssh/known_hosts
Cristian Ciupitu
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Stanley Williams
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  • hi i already have a .pub then it is need to create public key again – Amit Bera Aug 20 '14 at 12:19
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    If you came here looking for how to do it in windows, run "puttygen yourkey.ppk", and then under the Conversions menu choose "Export OpenSSH key" to get the private key. – Ryan Shillington Sep 22 '14 at 16:46
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    the solution from @jous is much nicer since you don't need the private key to convert a public key + you don't need to install putty – Tobi Aug 19 '15 at 12:55
  • I had to add this key to my ./ssh/config file Host mysite.com Hostname mysite.com IdentityFile ~/.ssh/id_dsa IdentitiesOnly yes – vladkras Jan 12 '16 at 16:33
  • Some elliptic curve formats (ECDS etc) are only available in the beta putty tools yet. – Daniel W. Mar 23 '16 at 10:27
  • Never, ever set a Linux/Unix file to permissions "666" unless you have a very good reason. Both examples here should be 644 - others should be allowed to read, but never allowed to write to SSH related files. – Michael Firth Aug 02 '23 at 08:54
49
ssh-keygen -i -f id_dsa_1024_a.pub > id_dsa_1024_a_openssh.pub
  • -i flag is import from other than openssh format
  • -f flag means read from input file

Source: a blogpost at burnz.wordpress.com

jous
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    .ppk files are the full key pairs, I don't think the command above or the blog post apply to that. – Peter Becker Feb 07 '13 at 00:27
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    I think I meant that it works if you use puttygen's "Save public key" button. ssh-keygen do not understand true .ppk files because they lack those '---- BEGIN SSH2 PUBLIC KEY ----' markers. You can find the public key in the .ppk file between lines "Public-Lines:.." and "Private-Lines:.." though. – jous Jan 07 '14 at 14:35
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    This worked for me with a public-key file - puttygen seems to require a private key. it's seems that all it did was rearrange the base-64 part into a single line – Jasen Mar 12 '15 at 03:10
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    This does not seem to cover private keys, which is why I would want to do the conversion, I already have a public key saved somewhere... – Gert van den Berg Feb 06 '16 at 09:47
  • Yeah, the ppk files I've seen have had the appropriate markers, and this has worked just fine. – tylerl Sep 08 '19 at 21:40
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Get the private key:

open the .ppk file in puttygen:

puttygen ~/.ssh/id_dsa.ppk

export as openssh:

Conversions → Export OpenSSH key

Get the public key:

open like before the private key with puttygen, the public key is under public key for pasting into OpenSSH authorized_keys file

Bar Horing
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9

I prepared a Docker container to make life simpler:

docker run --rm \
           --volume=/path/to/file.ppk:/tmp/id_dsa.ppk \
           --volume=/path/to/output:/tmp/out/ \
           czerasz/putty-tools

Where:

  • /path/to/file.ppk - local path to your ppk file
  • /path/to/output - local path to where the private and public key should be placed
czerasz
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