While in college I decided to have a randomly generated 16 character password. I used parts of that password in various sites. However, one of the sites was compromised so I had to change my password.
I now have a randomly generated passwords per site. As you can imagine, it was difficult to learn the passwords and I resorted to carrying them around until I had learned them. This was essentially a small piece a paper with random passwords in a row. Were these passwords compromised I'd be a VERY unhappy camper.
Suppose that I am determined on having a random set of passwords and not liking a row of passwords plainly visible. I was considering the option of instead creating a grid of randomly generated characters and using various sub strings in the data as passwords.
Here is a worked example:
bqzryXrMjs wqpPcPW2tG CYvLdxGsnZ Hq9KDBJeN5 Z2v5H2BG6G JYNyWGLqEa
Password: Start at (2,3). Use every other character from left to right, wrapping rows as necessary. Length 10.
Using these instructions I generate password:
Note, that (2,3) was zero-indexed. Granted, those instructions are difficult to follow, but its just a skill to become better at. In practice I would use a larger grid and possibly a more complex pattern.
My question is how safe is this system. I know safe could mean lots of things. I'm not sure if cryptographically secure applies but I'm really just trying see if it would be reasonable to use this system to manage my passwords.
I can imagine a Bones episode where someone tracks my eye movements to determine what characters I'm reading... so suggestions like this are welcome but more practical/reasonable vulnerabilities are what I'm looking for.
For the purposes of limiting the scope of the question suppose the following:
Passwords are of length 10 Grids are of dimension 20x20 The only instruction available is one similar describe above. Start at (x,y) Use every other character from left to right, wrapping rows as necessary. Length 10. They are not allowed means that could be used to steal general private information such as a key logger, aggressive interrogation, etc.