kaniini/ecdsatool

ECDSA-CHALLENGE keypair manipulation tools and library

ecdsatool

Copyright (c) 2013 William Pitcock [email protected].

This software is free, but copyrighted software. See COPYING for terms and conditions.

what is this?

This tool creates and manipulates ECC NISTP256 keypairs, as used by the proposed ECDSA-NIST256P-CHALLENGE IALv3.2 mechanism.

It is built ontop of a library called libecdsaauth, which provides primitives for patching ECDSA challenge support into pre-existing clients and daemons.

Also a modified version of the Irssi cap_sasl.pl script is included, which uses ecdsatool to do the authentication, because Perl is hopeless and doesn't have a working ECDSA implementation. Use the ECDSA-NIST256P-CHALLENGE mechanism with /sasl set.

how to use the tool?

First, lets create a keypair, and store it in /home/nenolod/irc.pem:

$ ecdsatool keygen /home/nenolod/irc.pem
A9T8WQPtyWlP0sEFQaugzQjWHH+hmoRIfFl7yaADaagb

This creates a new ECC NISTP256 keypair and stores it in /home/nenolod/irc.pem. The value returned by ecdsatool is the public key, which you may register with services.

Presently, to do that on Atheme, you would set it as a NickServ property. A better interface for key enrollment will be added soon. To do this, run the following command on IRC:

/msg nickserv set property pubkey A9T8WQPtyWlP0sEFQaugzQjWHH+hmoRIfFl7yaADaagb

recovering the public key from a private key?

Use the pubkey subcommand:

$ ecdsatool pubkey /home/nenolod/irc.pem
A9T8WQPtyWlP0sEFQaugzQjWHH+hmoRIfFl7yaADaagb

interrogating information about keypairs?

Use the keyinfo subcommand:

$ ecdsatool keyinfo /home/nenolod/irc.pem
Information on /home/nenolod/irc.pem:
    Private-Key: (256 bit)
    priv:
        00:92:0c:69:ac:48:6b:ef:7e:96:69:0a:94:4b:df:
        97:34:00:a8:96:8e:da:05:ec:20:5f:33:36:26:08:
        b1:51:e5
    pub: 
        03:d4:fc:59:03:ed:c9:69:4f:d2:c1:05:41:ab:a0:
        cd:08:d6:1c:7f:a1:9a:84:48:7c:59:7b:c9:a0:03:
        69:a8:1b
    Field Type: prime-field
    Prime:
        00:ff:ff:ff:ff:00:00:00:01:00:00:00:00:00:00:
        00:00:00:00:00:00:ff:ff:ff:ff:ff:ff:ff:ff:ff:
        ff:ff:ff
    A:   
        00:ff:ff:ff:ff:00:00:00:01:00:00:00:00:00:00:
        00:00:00:00:00:00:ff:ff:ff:ff:ff:ff:ff:ff:ff:
        ff:ff:fc
    B:   
        5a:c6:35:d8:aa:3a:93:e7:b3:eb:bd:55:76:98:86:
        bc:65:1d:06:b0:cc:53:b0:f6:3b:ce:3c:3e:27:d2:
        60:4b
    Generator (compressed):
        03:6b:17:d1:f2:e1:2c:42:47:f8:bc:e6:e5:63:a4:
        40:f2:77:03:7d:81:2d:eb:33:a0:f4:a1:39:45:d8:
        98:c2:96
    Order: 
        00:ff:ff:ff:ff:00:00:00:00:ff:ff:ff:ff:ff:ff:
        ff:ff:bc:e6:fa:ad:a7:17:9e:84:f3:b9:ca:c2:fc:
        63:25:51
    Cofactor:  1 (0x1)
    Seed:
        c4:9d:36:08:86:e7:04:93:6a:66:78:e1:13:9d:26:
        b7:81:9f:7e:90

signing challenges from scripts?

Use the sign subcommand.

$ ecdsatool sign /home/nenolod/irc.pem 'QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUE='
MEUCICNBUzxaMXcqyec7q0aZcHMa0HY9NELX869/8tjd58cFAiEA75FzpxmPOcotr0vc8ncEM79DoQRf/bOSoi1yK5X67J8=

mechanism spec?

Similar to EXTERNAL:

1. Start authentication by sending AUTHENTICATE ECDSA-NIST256P-CHALLENGE.
2. Wait for an ACK from the IRC network.
3. Send the accountname encapsulated in base64.
4. Wait for the challenge message from the IRC network.
5. Sign the message and send it back, using ecdsatool sign or the library API.
6. If everything went to plan, authentication should be successful, and you'll be able to get on the network.