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== YubiKey C Client Library: libykclient ==
YubiKey C Client Library (libykclient) is a C library used to validate
an Yubikey OTP against Yubico's servers. See[the Yubico website]
for more information about Yubico and the YubiKey.
=== Building ===
After downloading and unpacking the package tarball, you build it as
make check
sudo make install
=== 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 git://
This will create a directory 'yubico-c-client'. Enter the directory:
cd yubico-c-client
Recent versions of autoconf, automake and libtool must be installed.
Help2man is used to generate the manpages. Libcurl development files
(headers and *.so) must also be installed.
Generate the build system using:
autoreconf --install
Then refer to the user sections above regarding building.
=== Command-line tools ===
There is one command line tool, ykclient, to validate a particular
OTP. It needs a client id, which you can generate[here].
Example usage:
[source, sh]
jas@mocca:~/src/yubico-c-client$ ./ykclient
Usage: ./ykclient <client_id> <yubikey_otp>
CLIENT_ID: your client id integer
YUBIKEY_OTP: One-time password generated by yubikey
jas@mocca:~/src/yubico-c-client$ ./ykclient --debug 16 ccccccbchvthlivuitriujjifivbvtrjkjfirllluurj
client id: 16
token: ccccccbchvthlivuitriujjifivbvtrjkjfirllluurj
Verification output (2): Yubikey OTP was replayed (REPLAYED_OTP)
=== 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.
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