Here are some subjective databases (images and observers’ scores) dealing with watermarking and encryption distortions :
H.264 watermarking T. Stutz and F. Autrusseau, "H.264/CAVLC Structure preserving watermarking", 2011.
Selective Encryption F. Autrusseau, T. Stutz and V. Pankajakshan, "Subjective quality assessment of selective encryption techniques", 2010.
Broken Arrows F. Autrusseau, P. Bas "Subjective Quality assessment of the Broken Arrows watermarking technique", 2009.
DT-CWT vs DWT F. Autrusseau, Peter Meerwald, "DT-CWT versus DWT watermark embedding", 2009.
Fourier domain embedding F. Autrusseau, "Fourier sub-band embedding", 2008.
Watermarking Quality benchmark Enrico Marini, Florent Autrusseau and Patrick Le Callet, "Evaluation of standard watermarking techniques", 2007.