SDK v0.10.0Game asset packaging & streaming

Your assets.
One archive.
Ready to load.

Pack your game’s files into one archive. Load them by path, check their integrity and protect them with your own key—in the engine you already use.

Explore integrations

Works offlineNo runtime royaltyBuilt in Rust

ASSET PIPELINEFiles → archive → engine

Textures

Meshes

Audio

Data

game.cpk

One archive. Read by path.

CPK3

textures/skybox.exrBLAKE3

meshes/hero.meshBLAKE3

audio/ambient.oggBLAKE3

Your engine

mount → read(path)Optional archive sealing

Your engine.
Your workflow.

Unreal Engine 55.4+ · Beta plugin

Unity 6UPM package · Beta

Godot 44.3+ · GDExtension · Beta

Your engineC / C++ API

01 / The archive layer

Pack once.
Keep your workflow.

A single place to package, mount and read your assets, with control over updates and protection.

01 — READ

Fewer copies in memory.

Read uncompressed, unsealed files directly from a memory-mapped archive. Compressed or sealed files decode into a buffer.

02 — LAYER

Base game. DLC. Mods.

Mount archives in layers. A patch or mod overrides the same path in the base game without rebuilding the original archive.

03 — UPDATE

Ship what changed.

Build chunk patches that contain only changed content. Your game or launcher delivers them; CyclePack handles the archive tools.

04 — AUTOMATE

Fits your build process.

Use Lua 5.4 scripts for build steps or integrate through Rust and the C API. The library runs offline with no licence server.

Choose the right archive mode. Chunk patches save nothing on sealed archives, which are encrypted afresh on each pack. Archives written by Lua use an older format without per-file fingerprints or sealing.

02 / How it fits

One path.
The right version.

Your engine sees files, not a pile of archives. CyclePack resolves each path to the highest-priority mounted layer.

1
Package your files
Create a CPK3 archive with integrity fingerprints and optional sealing.
2
Mount your archive layers
Keep the base game, DLC and patches in separate archives.
3
Read by path
Ask for an asset. The highest-priority matching archive wins.

MOUNTED ARCHIVESHighest priority first

patch.cpkUpdated character mesh

Selected

dlc.cpkAdditional content

DLC

base.cpkOriginal game assets

Base

YOUR ENGINE ASKS FOR

meshes/hero.meshRead from patch.cpk

Example mount order. Your game chooses the archives and their priorities.

03 / Integrity & protection

Know what you load.
Control who can read it.

Verify each file against its recorded fingerprint. Seal the archive under your own key when its contents need protection.

Damage gets a name.A failed check identifies the affected file.

Your archive. Your key.AES-256-GCM or ChaCha20-Poly1305 sealing.

Refuse an older build.A sealed archive carries a generation number.

Read the security details

cyclepack / recorded runsmacOS 26.2 · Apple silicon

A clean archive passes. Change one byte and the check names the file.

$ cyclepack verify --input game.cpk
Verifying archive...
Structural validation passed. Archive format: CPK3, Entries: 8
Content integrity: 8 of 8 entries verified against the digests in the archive.
Verification passed: all 8 entries decoded and matched the digests CPK3 records

exit 0

$ cyclepack verify --input bad.cpk
Verifying archive...
Structural validation passed. Archive format: CPK3, Entries: 8
FAIL meshes/hero.mesh: E_DIGEST_MISMATCH: BLAKE3 digest mismatch
Error: Verification failed: 1 of 8 entries do not match the digest the archive records for them (meshes/hero.mesh: E_DIGEST_MISMATCH: BLAKE3 digest mismatch)

exit 1

Without the key, nothing inside can be listed or checked. With it, every file is checked.

$ cyclepack verify --input sealed.cpk
Verifying archive...
Structural validation passed. Archive format: CPK3 (sealed manifest), Entries: not readable without the key
Error: Verification failed: the manifest is sealed and no entry was checked. Nothing is known to be wrong with this archive; pass --key-file to verify it, or --structural-only to accept the header and length checks alone.

exit 1

$ cyclepack verify --input sealed.cpk --key-file key.bin
Verifying archive...
Sealed manifest authenticated (ChaCha20-Poly1305, generation 7).
Structural validation passed. Archive format: CPK3, Entries: 8
Content integrity: 8 of 8 entries verified against the digests in the archive.
Verification passed: all 8 entries decoded and matched the digests CPK3 records

exit 0

The doctor reports the capability backing on this Mac: what runs on real hardware here, and what runs on the CPU.

$ cyclepack doctor
…
  Memory Mapping:  [OK] POSIX mmap / MapViewOfFile (Lease-backed Zero-Copy)
…
    └─ Linux io_uring:  [--] Unavailable (io_uring is a Linux-native kernel interface; running on macos)
[Capability Backing]
  [EM] DirectStorage                Emulated     CPU queue with the same semantics; DirectStorage is a Windows interface
…
  [EM] BaM / io_uring               Emulated     pread/mmap with no ring; no io_uring ring could be set up here
  [EM] CXL shared memory            Emulated     process-local or file-backed shared memory, not a CXL fabric
  [EM] NVMe ZNS                     Emulated     in-memory zone model; zoned block devices are a Linux interface
…
  [EM] Computational storage        Emulated     host-CPU byte loop (XOR, not a cipher); no NVMe TP 4091/4092 device is used
  [EM] GPUDirect Storage            Emulated     host-memory bounce buffers; cuFile / GPUDirect Storage is not linked
  [EM] RDMA / RoCE v2               Emulated     in-process transport; no verbs provider or RoCE v2 NIC is used
…
The doctor reports what these probes established; it opens no archive and moves no I/O.

exit 0

Recorded on 1 October 2026. Pasted as printed; a line reading “…” marks a cut.

Sealing is not DRM. A game that opens sealed archives ships the key. Anyone who extracts it can read the assets. Verify archives at installation: direct memory-mapped reads skip the per-read integrity check.

Hardware acceleration: what runs natively today?

The Rust library uses Linux io_uring when the kernel permits it and falls back to ordinary reads. It has run on one Linux kernel in a container; the C API and engine plugins do not use this backend. CXL memory can map a Linux DAX device, but has not been tested on real CXL hardware.

DirectStorage, GPUDirect Storage, NVMe ZNS, RDMA and computational storage are CPU models labelled Emulated. GPU-memory requests are refused unless you explicitly allow an emulated path. No speed benchmark has been published for this release.

Read the measurements and commands

04 / Engine integrations

Start in the engine
you already know.

Beta plugins for Unreal, Unity and Godot. A C API for your own engine, with one header and one library.

Unreal Engine 5.4+ Beta

// In YourProject.Build.cs
PublicDependencyModuleNames.AddRange(new string[] { "CyclePackRuntime" });

// In your Game Mode or startup module (UE 5.4+, IPlatformFile layer):
if (FCyclePackPlatformFile* Vfs = FCyclePackPlatformFile::Get())
{
    Vfs->MountCpk(TEXT("World/"), TEXT("Content/Paks/WorldData.cpk"));
}

Current status: reads CyclePack archives through Unreal’s file layer and I/O dispatcher. It has not run inside Unreal yet; part of the code was compile-checked against stand-in headers. It does not read .pak or .utoc files.

Unity 6 · UPM package Beta

// In Packages/manifest.json:
//   "com.cyclechain.cyclepack": "file:../integrations/unity/com.cyclechain.cyclepack"
using CyclePack;

var vfs = new CyclePackRuntime();
vfs.Mount("assets/", Application.streamingAssetsPath + "/game_assets.cpk");
byte[] modelBytes = vfs.Read("assets/characters/hero.mesh");

Current status: mounts archives and reads files from C#. Tested outside the Editor with .NET 8 on macOS. Unity Editor and IL2CPP runs are still to come.

Godot 4.3+ · GDExtension Beta

# Godot 4.3+ GDScript, through the GDExtension in integrations/godot/CyclePack
var vfs = CyclePackRuntime.new()
vfs.mount("assets/", "res://data.cpk")  # res:// is globalized for you
var texture_data: PackedByteArray = vfs.read_file("assets/skybox.exr")

Current status: mounts archives and reads files from GDScript. Runs on Godot 4.7.2 in headless mode. Exported games have not been tested yet.

C / C++ · Native API

#include <cstdio>
#include <cyclepack.h>

int main() {
    // A single-file CPK3 archive is its own index: the same path goes in twice.
    CyclePackUnpacker* vfs = cyclepack_create_unpacker("game.cpk", "game.cpk");
    if (!vfs) return 1;

    // Borrows the mapped bytes: no copy, nothing to free. NULL for an absent,
    // compressed or sealed entry; valid until cyclepack_destroy_unpacker.
    uint32_t size = 0;
    const uint8_t* bytes = cyclepack_get_data_ptr(vfs, "meshes/hero.mesh", &size);
    if (bytes) {
        std::printf("borrowed %u bytes of meshes/hero.mesh\n", size);
    }

    cyclepack_destroy_unpacker(vfs);
    return 0;
}

Output

borrowed 5000 bytes of meshes/hero.mesh

Checked: compiled with c++ -std=c++17 -Wall -Wextra against cyclepack.h and libcyclepack, no warnings, then run on game.cpk, the archive the integrity check above verifies. Borrowed bytes are valid until the unpacker is destroyed; compressed, sealed or absent entries return NULL.

Before you integrate: plugins currently mount unsealed archives. Keyed mounts are available through the C API. The library was tested on Apple silicon macOS and arm64 Linux in a container. Windows, Intel Macs and x86-64 Linux are not yet tested; console, iOS and Android builds are unavailable. Rust, Python and Node packages and a browser WebAssembly reader are also included. Web mode is a preview and is not DRM.

Explore the whitepaper

05 / Licensing

A licence for your title.
No runtime royalties.

Start free as an indie studio. Evaluate before buying as a larger team. Pro and Enterprise licences are per title.

Indie

Free named licence

Unlimited titles

For studios with revenue plus funding under $200,000 over the last 12 months.

All core archive features
Beta engine plugins and C API
Community support
0% runtime royalty

Pro

For production teams

$2,500

Per title · One time

For titles with a production budget up to $2,000,000.

Everything in Indie
C++ drivers included
12 months of SDK updates
48-hour support · No seat limit
0% runtime royalty

Enterprise

Custom terms

from $15,000

Per title · Studio agreements available

For production budgets over $2,000,000 and teams that need source access.

Everything in Pro
Source for each licensed release
8-hour priority support
Custom licensing terms
0% runtime royalty

In every tier

Archive format · Zero-copy reads · Integrity checks · AES-256-GCM / ChaCha20-Poly1305 sealing · Beta Unreal, Unity and Godot plugins · C API · Lua scripting · Layered mounts · Patching tools

Compare licence and support details

CyclePack licence comparison
Licence & support	Indie	Pro	Enterprise
Titles	Unlimited	One licence per title	Per title or studio agreement
Runtime royalty	0%	0%	0%
C++ drivers	Not included	Included	Included
Source code	Not included	Not included	Each licensed release; not repository history
Support	Community	48 hours	8 hours, priority
Evaluation	Not needed	30 days above the Indie threshold; no commercial release

Pro renewal is optional: shipped titles keep working on the version they shipped with. Nothing in v0.10.0 checks a licence or locks a command, tool or feature.

06 / A few useful answers

Before you
start building.

What CyclePack does, where it fits and what this release supports.

What is CyclePack?

A Rust SDK for packaging, protecting and loading game assets. Your engine mounts an archive like a folder and reads files by path. Use an engine plugin or integrate through the C API.

Is every asset read zero-copy?

No. Only uncompressed, unsealed entries can be borrowed directly from the memory-mapped archive. Compressed and sealed entries decode into a buffer. Direct reads skip the per-read integrity check, so run cyclepack verify when installing an archive.

Can players extract sealed assets?

They need the key, but a game that opens its own archives ships that key. Anyone who extracts it can read the contents. Sealing protects against access without the key and unnoticed changes; it is not DRM.

Which engines and platforms can I use?

Beta plugins target Unreal 5.4+, Unity 6 and Godot 4.3+. The C API supports custom engines. This release was tested on Apple silicon macOS and arm64 Linux in a container. Windows, Intel Macs and x86-64 Linux are untested. No console, iOS or Android build is available.

Does CyclePack replace my launcher or patch delivery?

No. CyclePack builds and applies chunk patches; your game or launcher delivers them. Chunk patches save nothing on sealed archives because each pack encrypts them afresh.

Does it need a connection or a runtime royalty?

The library opens no network connection, sends nothing home and uses no licence server. Every tier has a 0% runtime royalty. Indie is free under the $200,000 revenue-plus-funding threshold; Pro is $2,500 per title and Enterprise starts at $15,000.

Build with CyclePack

Put your assets to work.

Tell us about your engine, platform and title. Start with an Indie licence or a 30-day evaluation.

Read the whitepaper

Your assets.One archive.Ready to load.

Pack once.Keep your workflow.

Fewer copies in memory.

Base game. DLC. Mods.

Ship what changed.

Fits your build process.

One path.The right version.

Package your files

Mount your archive layers

Read by path

Know what you load.Control who can read it.

Start in the engineyou already know.

A licence for your title.No runtime royalties.

Indie

Pro

Enterprise

In every tier

Before youstart building.

Put your assets to work.

Your assets.
One archive.
Ready to load.

Pack once.
Keep your workflow.

One path.
The right version.

Know what you load.
Control who can read it.

Start in the engine
you already know.

A licence for your title.
No runtime royalties.

Before you
start building.