Back in the 60’s & 70’s that was the technique that most self defense instructors recommended for women trying to get home after dark. I think the ultimate destination was to gouge the keys into the assailant’s eyes or scraping them down a cheek. I did carry my car keys & house keys wedged between my fingers just in case I needed them. Fortunately for me, I NEVER had to test them to see IF it worked!!! In theory, it made sense; but as I said, I was blessed to not have to use it to know for sure!!!
Now days, I have a small, very sharp pocket knife that I keep on my house key ring & my car key ring. It folds up & I open it up & have it in my hand whenever I have to go out at night. I’m thinking that I’d have a chance to stab the creep in the eye; or at the least, I could cut his arm & fingers or maybe the nose if I missed the eyes. It’s not strong enough to stab somebody with; but, is sharp enough to leave some painful slices.
Scratching them with the keys should give some good DNA evidence as well as a noticeable wound!!!
In my opinion, the best way to maintain your safety is to be fully aware of your surroundings. When anyone approaches, look them in the eyes & study their facial features. That seems to unnerve many because it means that you can give a full description of them to the cops. When walking through a parking lot or down a sidewalk, I’m constantly looking around so I’m aware where any strangers are located. That tends to unnerve them as it tells them that you are aware of where they’re located & will make their attempt to snatch your purse more difficult because you’re anticipating what might happen. Supposedly, your self confidence helps to diminish their self confidence & they will choose a different victim for their own safety!!!