nrodecrypt

Decrypts a GRF for NightmareRO.

Requirements

• dotnet 9 runtime

gui Usage

• Open nrodecrypt-gui.exe
• Click "Browse" or drag the GRF into the window
• Click "Decrypt"
• A file named <file>_decrypted.grf is created relative to the GRF you selected

cli Usage

nrodecrypt <archive.grf> [-o out.grf] [-k cps.dll] [-f]
nrodecrypt decrypt <archive.grf> [-o out.grf] [-k cps.dll] [-f]
nrodecrypt extract <archive.grf> <outdir>  [-k cps.dll] [-c 1252]
nrodecrypt verify  <archive.grf> [-c 1252]
nrodecrypt key     [cps.dll]

option	meaning
-o, --out <path>	output archive (default <name>_decrypted.grf)
-k, --dll <path>	DLL holding the key; omit to probe every *.dll/*.exe beside the archive
-c, --codepage <n>	filename codepage, default 1252; use 949 for Korean paths
-f, --force	overwrite an existing output
--only <path>	extract just this GRF path (repeatable); / and \ equivalent, case-insensitive
--list <file>	read paths from a file, one per line (# comments and - bullets ignored)
--flat	write basenames into the output dir, no directory tree
--keep-info	keep __encryption.info (dropped by default - its presence makes GRF Editor prompt for a key)

Exit codes: 0 ok, 1 usage/IO error, 2 some entries unresolved, 3 verification failed.

Example

> nrodecrypt dream.grf
archive: dream.grf
         signature "Event Horizon R"  version 3.0  entries 2766
         table header 12B, records 21B, count field literal
key    : jem.dll @0x294A4  seed=0x0F3E0FFB  (auto-detected, code pattern, validated on 5 entries)

decrypted   : 2765
dropped     : 1  (__encryption.info)
failed      : 0
written     : 2765 entries -> dream_decrypted.grf

=== verifying output ===
         table ends at 66995574 / file 66995574   EXACT FIT
inflated OK : 2765
failed      : 0
RESULT: OK

Build

dotnet publish cli -c Release -r win-x64 --self-contained false -o dist

Requires the .NET 9 runtime. Add --self-contained true for a standalone exe.