If you don't mind me asking: Do you (a) harden your brainwallet using a script, similar to OP, or do you (b) rely on a technique that you can apply off the top of your head, without relying on a computer? (eg. a long passphrase that is not part of a known body of literature, changing / shifting letters around in a way that can be easily remembered...)
Both make sense when trying to avoid storing data outside your head, but (a) seems more secure while (b) gives you full flexibility regardless of whether you have access to your hardening script.
Both make sense when trying to avoid storing data outside your head, but (a) seems more secure while (b) gives you full flexibility regardless of whether you have access to your hardening script.
What does it matter?
However I hardened my passphrase, I'm not going to unharden it now by telling you about this.
Although (brain wallet produced by human) --> seed key
is recognized and accepted as a bad idea,
f(brain wallet produced by human) --> seed key
where f is a easily remembered math procedure such as modulo(x), may form an acceptable key
Question being, whether a simple obfuscation algorithm that can be done in your head or with a piece of paper is sufficient, as opposed to a computer-supported one. Unless you can mentally sha256
Given the amount of possible simple obfuscation algorithms I guess one can achieve sufficient security without computer support, assuming you don't rely on any well known methods (rot13 anyone?). In other words, this could be a use case where rolling your own "crypto" and security by obscurity might be a good thing.