proc av_des_alloc(): ptr AVDES {.importc, cdecl, ...raises: [], tags: [],
                                 forbids: [].}

proc av_des_crypt(d: ptr AVDES; dst, src: ptr uint8; ccount: cint;
                  iv: ptr uint8; decrypt: cint) {.importc, cdecl, ...raises: [],
    tags: [], forbids: [].}

proc av_des_init(d: ptr AVDES; key: ptr uint8; key_bits, decrypt: cint): cint {.
    importc, cdecl, ...raises: [], tags: [], forbids: [].}

proc av_des_mac(d: ptr AVDES; dst, src: ptr uint8; count: cint) {.importc,
    cdecl, ...raises: [], tags: [], forbids: [].}