{.push raises: [].}

import std/random

import winim

type

USTRING = object

Length, MaximumLength: DWORD

Buffer: PVOID

proc makeRandomBytes(i: int): seq[uint8] =

for k in 0 .. i:

result.add(rand(255).uint8)

proc rc4EncryptNTAPI(data, key: PTR): NTSTATUS

{.discardable, stdcall, dynlib: "Advapi32", importc: "SystemFunction032"}

proc rc4Encrypt*(key, payload: seq[uint8], winapi: bool): string {.raises: [OSError].} =

if winapi:

var

winPayload = payload # need a deep copy because of in-place memory modification

key = USTRING(

Length: cast[int32](key.len),

MaximumLength: cast[int32](key.len),

Buffer: key.addr # can't use `ptr` because it is a generic

)

data = USTRING(

Length: cast[int32](winPayload.len),

MaximumLength: cast[int32](winPayload.len),

Buffer: winPayload.addr

)

status = rc4EncryptNTAPI(data.addr, key.addr)

if not status.NT_SUCCESS:

echo &"[-] Encryption failed with code: {status}"

raise newException(OSError, "Encryption failed using NTAPI")

result = $data