Evolution of fast , radiative shocks in high density medium is presented .
Ionizing spectra and approximate broad band light curves of the shocked gas are calculated .
Emergent shock spectra , as seen by a distant observer , are obtained from photoionization models .
The emergent spectra have a power-law shape F _ { \nu } \propto { \nu } ^ { - \alpha } with mean spectral index \alpha \sim 0.6 - 1.0 in the energy range 0.01 - 10 keV , and have a high-energy cutoff corresponding to the original shock velocity .
It is shown that the models exhibit promising features that may account for some photometric and spectral properties of Active Galactic Nuclei .