Kerberos AES256 and constants

[Egor]

Good day.
I am searching for detailed AES256 kerberos algorithm implementation.
I am interested espeсially in nfold algorithm in it. I know, how nfold algorithm works, but it is very important for me to know, which constants except string "kerberos" are used in key derivation with the help of nfold algorithm. I have heard that these constants depends on the type of traffic packet (AS_REG, AS_REP, TGS_REP)
Could you please help to find it, it is very important?