The Skeleton Key once again requires energy to empower it. The Exo Stranger believes that energy from the radiolarian fluid inside Vex and the usage of Stasis abilities should help you do so.
"Poring through Clovis's journal revealed to me just where his next decryption algorithm is hidden, and how to empower the Skeleton Key to access it. The answer lies in the Vex, and as always, Darkness." —The Exo Stranger