/usr/lib/x86_64-linux-gnu/libtcpcrypt.so is in libtcpcrypt-dev 0.5-1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libtcpcrypt.so.0.0.0
/usr/lib/x86_64-linux-gnu/libtcpcrypt.so.0.0.0