The solution is a 32 characters long plain-text (the private key).
As far as I know, there is no 32 character private key. A
mini private key would have 30 characters.
every character is represented as 1 byte and considering a private key is 32 bytes you can simply convert a 32 char long string to a 32 byte long byte array and use it as a private key.
for instance this sentence ("Hi this is satoshi nakamoto comb") is 32 byte long and can be represented as "10f0c810a0c56a1282574ce4bf9d3e843afc5be688c277ab75e6da1e6f95d756" in base16 or "Kwne8vNfRRiq8d6CB6YpCtbK6EKCRyoCjPGomLshKgubBWwiDQWD" in base58 WIF.
That's called a brainwallet:
https://brainwalletx.github.io/no, that is not called "brain wallet". it is not called anything actually. you are choosing the private key in a silly manner, that's all. a brain wallet has no restrictions for how long the input should be (the 32 byte) so it can be a 1 letter input or an essay of couple of pages long. and that is simply because they hash it to reduce the size.
Hex should be: 48692074686973206973207361746f736869206e616b616d6f746f20636f6d62
lol, i don't know why but i was passing the SHA256 hash of it as the bytes instead! fixed it