dev-libs/opensc/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>crypto</herd>
  <longdescription>
    OpenSC is a library for accessing SmartCard devices. It is also
    the core library of the OpenSC project.

    Basic functionality (e.g. SELECT FILE, READ BINARY) should work on
    any ISO 7816-4 compatible SmartCard.  Encryption and decryption
    using private keys on the SmartCard is possible with PKCS #15
    compatible cards, such as the FINEID (Finnish Electronic IDentity)
    card.
  </longdescription>
  <use>
    <flag name='libtool'>
      Use <pkg>sys-devel/libtool</pkg> for dynamically loading libraries
      rather than the host libdl/dlopen helpers.
    </flag>

    <flag name='openct'>
      Use <pkg>dev-libs/openct</pkg> (and CT-API) for accessing
      Smartcard hardware.
    </flag>

    <flag name='ctapi'>
      Use CT-API for accessing Smartcard hardware.
    </flag>

    <flag name='pcsc-lite'>
      Use <pkg>sys-apps/pcsc-lite</pkg> (and PC/SC API) for accessing
      Smartcard hardware.
    </flag>

    <flag name='secure-messaging'>
      Enable secure messaging.
    </flag>
  </use>
</pkgmetadata>