Convert PuTTY Private Key (ppk) to OpenSSH (pem)

Convert a PuTTY format private key file (.ppk) to OpenSSH (.pem).

Download Chilkat Ruby Library

require 'chilkat'

key = Chilkat::CkSshKey.new()

#  Load an unencrypted or encrypted PuTTY private key.

#  If  your PuTTY private key is encrypted, set the Password
#  property before calling FromPuttyPrivateKey.
#  If your PuTTY private key is not encrypted, it makes no diffference
#  if Password is set or not set.
key.put_Password("secret")

#  First load the .ppk file into a string:

keyStr = key.loadText("putty_private_key.ppk")

#  Import into the SSH key object:
success = key.FromPuttyPrivateKey(keyStr)
if (success != true)
    print key.lastErrorText() + "\n"
    exit
end

#  Convert to an encrypted or unencrypted OpenSSH key.

#  First demonstrate converting to an unencrypted OpenSSH key

bEncrypt = false
unencryptedKeyStr = key.toOpenSshPrivateKey(bEncrypt)
success = key.SaveText(unencryptedKeyStr,"unencrypted_openssh.pem")
if (success != true)
    print key.lastErrorText() + "\n"
    exit
end

#  Save to an encrypted OpenSSH PEM file:

bEncrypt = true
key.put_Password("myPassword")
encryptedKeyStr = key.toOpenSshPrivateKey(bEncrypt)
success = key.SaveText(encryptedKeyStr,"encrypted_openssh.pem")
if (success != true)
    print key.lastErrorText() + "\n"
    exit
end

print "Done!" + "\n"