[robmccoll]

You could split the key a few ways if you don't want to trust that one of your stores won't be compromised https://en.m.wikipedia.org/wiki/Shamir%27s_secret_sharing

[IncreasePosts]

Or, just apply some simple, easy to remember permutation to the key that no one would be likely to guess - eg rot13 the key, or add 1 to every character, move the first 14 characters of the key to the end of the key, etc.