Question about brainwallet and address creation.

[Bakemono]

Hello guys i 'm trying to understand some things about brainwallet.org

1) Is the "Secret exponent" the private ecdsa key?
2) Is the "Private key" the wallet import format?
3) What it the "Private key (DER)"

Thank you. 

[Valle]

1) I think it's sha256(input paper wallet phrase).
2) yes, it starts with "5" or "L" or "K"
3) it's "Distinguished Encoding Rules" - it's format for keeping information about private keys/names/hashes in the "other world".