Nick Szabo writes:

[...]some general ideas for "encrypting" (sic) one's image:

Some idea's are good, other's are abit off base. Major points of recognition are: jaw, cranium, nose, eyes, ears, age, and facial hair. Secondary points include: health, weight, optics, scars, etc. jaw: presence or lack of beards, highlighting skeletal lines, and hollows (aging) with makeup, or cigarette ash, plastic inserts in the cheeks, building up areas of the face with liquid latex, or morticians wax. (note that some of these techniques can be used on other areas of the face). cranium: hats, sudden changes in hair length/style, wigs (possably with padding). nose: highlighting/latex/wax - as with jaw, inserting a pair of small nuts/ buttons in the nose (drill for adequate airflow) will give the nose an appearence of having a "squashed/flattened" tip. 1/4 inch sections of stiff plastic tubing may also work. eyes: appear "sunken" w/ makup, altering eyebrows can misdirect eyesocket shape, pull back (oriental), or buldge out by pulling/gluing skin with spirit gum, or liquid latex. change color with tinted contacts. (note: sunken = old age, malnutrician, or sickness - pulling skin can also highlight cheekbones, etc.) ears: glue to the side of the head w/ rubber cement, spirit gum, or latex. age: 1) younger: very close shave, hot towles, alum, and talcum powder will tighten the skin, giving a youthfull appearence. 2) older: Max Factor hair whitener to grey temples, highlight lines and hollows of face (STUDY a stage makeup book, and prectice this before trying to fool anyone. Subtlety is the key with any realistic makeup, there is a tendency to over do it most of the time. As a rule of thumb cosmetic, and theatrical makeup is mostly worthless for disguise, and will not stand up to examination at close distances, unless well done, subtlely, and with extreme moderation.) facial hair: presence/absence, drastic changes in length, style and color can significantly alter ones appearence. Remember that neural nets, or a trained observer is going to be looking for the underlying skeletal shape, and building on top of that. health: depressed eye sockets, hollow cheeks, flush or jaundus (beta-kerotine) skin color. contra: exercise/good skin tone. Gaining or loosing weight, "sudden tan" type products... optics: glasses can hide features, and in some cases slightly alter the shape of the face. If unusual, they can be used as misdirection for an untrained observer (just like buttons, "loud" clothing, etc - as people tend to remember the unusual aspects, and not concentrate on usual features. Tinted contact lenses can change eye color. scars: hard to do right - use liquid latex, burns, cuts, etc. Probably best avoided, though very memoral to the observer, esp. if on the face. Misc: teath can be altered w/ iodine(stained), or blocked out with black wax. Have different "classes" of clothes (clergy, blue collar, white collar, "bum", etc - but stay in character. Remember that a construction worker isn't going to have an accountants hands, or imaculate tools, a bum will probably have dirt under their fingernails, etc. horizontal stripes make you look shorter/fatter, vertical ones taller/ skinnier. loud clothing, or pollitical buttons, a "funky" hat, etc will act as misdirection. skin acn also be bleached. consider: weight, muscle tone, stance, gait, etc. hair gell, and a curling iron are your friends :-)