ln5 / teneo

Regenerable ed25519 keys for OpenSSH

Teneo

Regenerable ed25519 keys for OpenSSH.

Teneo allows you to deterministically generate an ed25519 key pair for OpenSSH from a set of parameters. This allows you to (re)generate your key pair on a computer which, for example, lacks persistent storage.

You must be able to remember three things to (re)generate your key pair;

1. A user defined "username", which can be any string.
2. A Teneo defined "profile" name. There's currently only one profile available: 2015v1, which uses scrypt() + salsa20/8 + sha256 as KDF.
3. Your personally selected passphrase.

Usage

Usage: ./teneo [ options ] [ output directory ]

Help Options:
  -h, --help                Show help options

Key Options:
  -u, --user <username>     Specify which username to use
  -p, --profile <profile>   Specify which profile to use

  Available Profiles:
      2015v1

Output Format Options:
  -s, --openssh             Output OpenSSH public and private key

Example Usage

1. We start by creating a key pair for OpenSSH using [email protected] as username.

    $ ./teneo --openssh --user [email protected]
    Passphrase: foobar
    Generating key pair using the '2015v1' profile ...
    This may take a little while ...
    Succesfully generated key pair ...
    Saving OpenSSH secret key to id_ed25519 ...
    Saving OpenSSH public key to id_ed25519.pub ...
   
    $ cat id_ed25519
    -----BEGIN OPENSSH PRIVATE KEY-----
    b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
    QyNTUxOQAAACArYR91DYHLCeYb+Ls3wyYsSJrADs7topOSlioZ6GNX2AAAAJj36teu9+rX
    rgAAAAtzc2gtZWQyNTUxOQAAACArYR91DYHLCeYb+Ls3wyYsSJrADs7topOSlioZ6GNX2A
    AAAEAv/A/ak2U1vqbQR7sDFmJFp1eC7kv0HdZYm4Dt50n33ythH3UNgcsJ5hv4uzfDJixI
    msAOzu2ik5KWKhnoY1fYAAAAEWFoZkB0ZW5lby4weDkwLmRrAQIDBA==
    -----END OPENSSH PRIVATE KEY-----
   
    $ cat id_ed25519.pub
    ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICthH3UNgcsJ5hv4uzfDJixImsAOzu2ik5KWKhnoY1fY [email protected]
   
    $ openssl sha256 id_ed25519.pub
    SHA256(id_ed25519.pub)= a394eb08102eefb020d3274285671d113604690bedb551c5dfbf27c0d6844482
   

2. Wipe the key pair.

    $ rm -rf id_ed25519
    $ rm -rf id_ed25519.pub
   

3. Create the key again using the same parameters and passphrase.

    $ ./teneo --openssh --user [email protected]
    Passphrase: foobar
    Generating key pair using the '2015v1' profile ...
    This may take a little while ...
    Succesfully generated key pair ...
    Saving OpenSSH secret key to id_ed25519 ...
    Saving OpenSSH public key to id_ed25519.pub ...
   
    $ openssl sha256 id_ed25519.pub
    SHA256(id_ed25519.pub)= a394eb08102eefb020d3274285671d113604690bedb551c5dfbf27c0d6844482
   

Authors

• Alexander Færøy ([email protected]).

Todo

1. Code clean-up. This is a prototype written during two evenings of a weekend.
2. GnuPG format support.
3. Consider the new Tor ed25519 ID keys?
4. Add proper tests. Use Travis CI to build on both OS X and Linux.
5. Add fancy graphics after key generation, like the OpenSSH client, such that the user can quickly identify if something is wrong.
6. Add cracklib support and remember to make it possible to disable it as well.

License

See the LICENSE file.