libgfshare-bin binary package in Ubuntu Bionic amd64

 This package contains the gfsplit and gfcombine binaries.
 .
 gfsplit can be used to split a secret file (like a GPG secret key)
 into multiple parts, so that at least some number of those parts are needed
 to recover the original file, but any smaller combination of parts is useless
 to an attacker. gfcombine is used to combine the parts created by gfsplit.
 .
 For instance, you might split a GPG key using a 3-of-5 share and put one
 share on each of three computers, and two shares on a USB memory stick; then
 you can use the GPG key on any of those three computers using the memory
 stick, but if the memory stick is lost, you can recover the key by
 bringing the three computers together.

Source package