  Electron motion in an oblique shock wave is studied by means of a
one-dimensional, relativistic, electromagnetic, particle simulation code with
full ion and electron dynamics. It is found that an oblique shock can produce
electrons with ultra-relativistic energies; Lorentz factors with $\gamma \gto
100$ have been observed in our simulations. The physical mechanisms for the
reflection and acceleration are discussed, and the maximum energy is estimated.
If the electron reflection occurs near the end of a large-amplitude pulse,
those particles will then be trapped in the pulse and gain a great deal of
energy. The theory predicts that the electron energies can become especially
high at certain propagation angles. This is verified by the simulations.
