Select the region using the Rectangular Marquee Tool. Pull down menu Filter > Blur > Gaussian Blur Turn up the blur level until the image is indistinguishable in the preview.I have heard of some crafty people unbluring so this isn't ultra secure. Use a solid black rectangle for the most security.
Computer Tips - How can I blur an area of a photo for privacy using Photoshop?
Date: 2012aug23
Product: Photoshop
Q. How can I blur an area of a photo for privacy using Photoshop?
A. First, do NOT use the teardrop-shaped blur tool.
Instead, do this: