Your explanation has no mention of the blockchain. How would it be used? I use KeePass to generate and store very strong passwords. How would your system be better?
Your keepass database isn't global and therefore has to be carried on a usb, whereas the blockchain is accessible worldwide.
The user would create a master password or seed, and a table of random characters would be generated from the blockchain. The table would have co-ordinates, and the user would enter a pin code to reference a string of characters within the table. That string of characters can now be copied and used for a website password.
The website passwords wouldn't need to be written down. But the user would need to write down the master password and the username and pincode. The user would obviously have multiple pin codes for each website password to prevent reusing the same password for every website.
I store my keepass database in dropbox, so I can access it anywhere.
You don't need the blockchain to generate the random characters, do you? I guess you are suggesting that since the block chain is potentially globally accessible, you could use the block chain as the table.
