package atbash import "unicode" func Atbash(s string) string { r := []rune{} for _, v := range s { switch { case unicode.IsLetter(v): r = append(r, 'z'-unicode.ToLower(v)+'a') case unicode.IsNumber(v): r = append(r, v) } } ret := []rune{} for i, v := range r { ret = append(ret, v) if (i+1)%5 == 0 && i != len(r)-1 { ret = append(ret, ' ') } } return string(ret) }