I'm looking for a way of securely having passwords for different pages. Say I generate this password:
Then, for each site, I change a single character. It's a single, random position with a random character shift. Isn't it almost as secure as having a string half the length randomly generated, unpublished and not reused? Then I'd only have to remember the 1-64 character position + another number in my memory, instead of the whole password.
What pitfalls does this model have? I don't know how to measure the strength of this. I haven't used this model [yet], but I think it might be very useful for many people and situations, one being the case of a travel. The main problem I can see is a binary search can yield to, in average, 1/2 the strength of the whole thing (still kicking-ass strong).
To answer, please, consider that the position and shift are truly random. How much more secure is it if the original password is not published anywhere? Since I'm not specifically looking for security through obscurity, I'd like to know.
Note: I know about
correct horse battery staple and using a password manager, I'd just like to know if this is actually strong since I don't have the expertise to judge myself.