This work presents a new code-based key encapsulation mechanism (KEM) called\nLEDAkem. It is built on the Niederreiter cryptosystem and relies on\nquasi-cyclic low-density parity-check codes as secret codes, providing high\ndecoding speeds and compact keypairs. LEDAkem uses ephemeral keys to foil known\nstatistical attacks, and takes advantage of a new decoding algorithm that\nprovides faster decoding than the classical bit-flipping decoder commonly\nadopted in this kind of systems. The main attacks against LEDAkem are\ninvestigated, taking into account quantum speedups. Some instances of LEDAkem\nare designed to achieve different security levels against classical and quantum\ncomputers. Some performance figures obtained through an efficient C99\nimplementation of LEDAkem are provided.\n