in kdf_pbkdf2.go [58:64]
func (p pbkdf2Params) DeriveKey(password []byte, size int) (key []byte, err error) {
h, err := newHashFromPRF(p.PRF)
if err != nil {
return nil, err
}
return pbkdf2.Key(password, p.Salt, p.IterationCount, size, h), nil
}