YubiKey C Library: libyubikey

This package make up the low-level C software development kit for the Yubico YubiKey authentication device.

Building

After downloading and unpacking the package tarball, you build it as follows.

./configure
make check
sudo make install

Another way to build the package is with a hand written short makefile, invoke using make -f simple.mk check. This is usually not recommended, and you will have to read simple.mk for further information.

Building from version controlled sources

Warning! This is only for developers and if you don’t understand what you are doing, you should download the release files instead.

You may check out the sources using Git with the following command:

git clone https://github.com/Yubico/yubico-c.git

This will create a directory yubico-c. Enter the directory:

cd yubico-c

Recent versions of autoconf, automake and libtool must be installed, if you want to use the normal ./configure based approach. AsciiDoc’s a2x tool is also required for building the man pages. (See simple.mk if you want a slimmed down non-autoconf build approach.)

Generate the build system:

autoreconf --install

Then refer to the user sections above regarding building.

Command-line tools

The modhex program converts data between modhex, normal hex, and binary form.

The ykparse program decrypts and parses one OTP given the OTP and the AES key corresponding to that YubiKey.

The ykgenerate program constructs and encrypts one OTP given AES key and internal data values.

Example usage:

  $ ./modhex test
  ifhgieif
  $ ./modhex -d ifhgieif; echo
  test
  $ ./modhex -h b565716f
  nghgibhv
  $ ./modhex -h -d nghgibhv
  b565716f
  $ ./ykparse ecde18dbe76fbd0c33330f1c354871db dteffujedcflcindvdbrblehecuitvjkjevvehjd
  warning: overlong token, ignoring prefix: dteffuje
  Input:
    token: dcflcindvdbrblehecuitvjkjevvehjd
            20 4a 07 b2 f2 1c 1a 36 30 e7 df 89 83 ff 36 82
    aeskey: ecde18dbe76fbd0c33330f1c354871db
            ec de 18 db e7 6f bd 0c 33 33 0f 1c 35 48 71 db
  Output:
            87 92 eb fe 26 cc 13 00 a8 c0 00 10 b4 08 6f 5b

  Struct:
    uid: 87 92 eb fe 26 cc
    counter: 19 (0x0013)
    timestamp (low): 49320 (0xc0a8)
    timestamp (high): 0 (0x00)
    session use: 16 (0x10)
    random: 2228 (0x8b4)
    crc: 23407 (0x5b6f)

  Derived:
    cleaned counter: 19 (0x0013)
    modhex uid: jikdunvudhrr
    triggered by caps lock: no
    crc: F0B8
    crc check: ok
  $ ./ykparse ecde18dbe76fbd0c33330f1c354871db dteffujehknhfjbrjnlnldnhcujvddbikngjrtgh
  warning: overlong token, ignoring prefix: dteffuje
  Input:
    token: hknhfjbrjnlnldnhcujvddbikngjrtgh
            69 b6 48 1c 8b ab a2 b6 0e 8f 22 17 9b 58 cd 56
    aeskey: ecde18dbe76fbd0c33330f1c354871db
            ec de 18 db e7 6f bd 0c 33 33 0f 1c 35 48 71 db
  Output:
            87 92 eb fe 26 cc 13 00 30 c2 00 11 c8 9f 23 c8

  Struct:
    uid: 87 92 eb fe 26 cc
    counter: 19 (0x0013)
    timestamp (low): 49712 (0xc230)
    timestamp (high): 0 (0x00)
    session use: 17 (0x11)
    random: 40904 (0x9fc8)
    crc: 51235 (0xc823)

  Derived:
    cleaned counter: 19 (0x0013)
    modhex uid: jikdunvudhrr
    triggered by caps lock: no
    crc: F0B8
    crc check: ok
  $ ./ykgenerate ecde18dbe76fbd0c33330f1c354871db 8792ebfe26cc 0013 c0a8 00 10
  hcfktknicvbcnhbkvigcfhgddhhhrknc
  $ ./ykparse ecde18dbe76fbd0c33330f1c354871db `./ykgenerate ecde18dbe76fbd0c33330f1c354871db 8792ebfe26cc 0013 c0a8 00 10`
  Input:
    token: lihggvrgffbjnrehcgnkvknjkvubeekr
            a7 65 5f c5 44 18 bc 36 05 b9 f9 b8 9f e1 33 9c
    aeskey: ecde18dbe76fbd0c33330f1c354871db
            ec de 18 db e7 6f bd 0c 33 33 0f 1c 35 48 71 db
  Output:
            87 92 eb fe 26 cc 13 00 a8 c0 00 10 95 44 ec e9

  Struct:
    uid: 87 92 eb fe 26 cc
    counter: 19 (0x0013)
    timestamp (low): 49320 (0xc0a8)
    timestamp (high): 0 (0x00)
    session use: 16 (0x10)
    random: 17557 (0x4495)
    crc: 59884 (0xe9ec)

  Derived:
    cleaned counter: 19 (0x0013)
    modhex uid: jikdunvudhrr
    triggered by caps lock: no
    crc: F0B8
    crc check: ok
  $

License

The project is licensed under a BSD license. See the file COPYING for exact wording. For any copyright year range specified as YYYY-ZZZZ in this package note that the range specifies every single year in that closed interval.