You're going about this the wrong way. What you want is to store the long part of the key in an easily-accessible form, but then have a small password that you know that secures it. There's actually a standard way to do this that is secure (well, as secure as your password): BIP38 encryption. Here are some sites that let you generate a BIP38-encrypted key: (I can't vouch for either of them personally, but they look decent enough)

https://bitcoinpaperwallet.com/bitcoinpaperwallet/generate-wallet.html
https://bit2factor.com/

BIP38 uses scrypt as a key stretcher, so that it's harder to guess your password (still, you should choose a good one, e.g. 8 random characters, not just a word or name).