Cambium

about

description

Cambium is an Android NIP-55 signer that holds no user keys. Cryptographic results come from a paired Heartwood hardware signer over NIP-46 (Nostr relays), with only safe, exact repeats answered from bounded per-identity caches. Amethyst, Primal and most other Amber-compatible clients cannot log in to a remote NIP-46 bunker directly, but they all support NIP-55 external signers. Cambium fills that gap: it registers as a signer, but it is not one. No user identity keys ever touch the phone. Compromising the phone exposes only the ability to request signatures, which the hardware signer's policy engine and physical confirmation button still gate, never the identity key itself. Phone unlock (opt-in): a Heartwood that restarts locked after a power cut asks this phone to unlock it. One tap and your screen lock send the board's unlock secret, which signs nothing and is useless without the board's own flash. Native approvals can be once, for an hour or day, or indefinite, with operation and signing-kind limits. Review and edit existing choices, test or reconnect a signer, and review a redacted diagnostic report before sharing it. Native Android apps can use Cambium silently while approved. Websites can use NIP-55 nostrsigner: links with an explicit one-shot approval and a validated HTTPS callback or clipboard result. Per-identity bounded priority queues keep user work available during relay-authentication bursts. No Google Play services, no Firebase, no analytics. Runs on any Android 8.1+ device, including GrapheneOS.

publisher

da19f1cd34beca44be74da4b306d9d1dd86b6343cef94ce22c49c6f59816e5bd

first seen

2026-09-24T20:21:25.085557+00:00

last event

2026-10-13 11:12 UTC

website

https://cambium.forgesworn.dev

install

zapstore.dev or any Zapstore-compatible client

topics

#nip46 #nip55 #nostr #security #signer

source & build

repository

https://github.com/forgesworn/cambium

arch flags

android-arm64-v8a android-x86_64

manifest

zapstore.yaml ok checked 2026-10-05T14:10:14.480236+00:00

{
  "icon": "./fastlane/metadata/android/en-US/images/icon.png",
  "license": "MIT",
  "name": "Cambium",
  "release_notes": "./CHANGELOG.md",
  "repository": "https://github.com/forgesworn/cambium",
  "summary": "NIP-55 signer that holds no keys \u2014 signing is proxied to a NIP-46 hardware bunker",
  "supported_nips": [
    "44",
    "46",
    "55"
  ],
  "tags": [
    "nostr",
    "signer",
    "nip55",
    "nip46",
    "security"
  ],
  "website": "https://cambium.forgesworn.dev"
}

releases (kind 30063)

4 releases indexed; latest 0.9.0.

assets & verification

Every app, release and asset event is schnorr-verified (NIP-01 id + signature) before it enters the catalog, and assets are content-addressed by sha256. We subscribe read-only to the catalog relay — never write to it.

0.9.0 — cambium-0.9.0.apk

sha256

3510781a23ec1e3c626a9c39ee31f968f4d4ca38d85f626b85c0d617c29fc16a

size

19.0 MB

archs

android-arm64-v8a, android-x86_64

version code

19

apk cert sha256

9ea188efa9015f7e7f90e1888f586f527b2a0e8a6dcdb3991e41fb4f14eeefc6

download

cambium-0.9.0.apk

0.8.0 — cambium-0.8.0.apk

sha256

81685c955f4ee164de761a196533307e5bd360190c2d1ad53c12266c237e5a11

size

18.9 MB

archs

android-arm64-v8a, android-x86_64

version code

18

apk cert sha256

9ea188efa9015f7e7f90e1888f586f527b2a0e8a6dcdb3991e41fb4f14eeefc6

download

cambium-0.8.0.apk

0.7.1 — cambium-0.7.1.apk

sha256

f95512296a1b6421dbcce9fa7346cd82fc9c177132f0ea5a70eea9d035231f1d

size

18.9 MB

archs

android-arm64-v8a, android-x86_64

version code

17

apk cert sha256

9ea188efa9015f7e7f90e1888f586f527b2a0e8a6dcdb3991e41fb4f14eeefc6

download

cambium-0.7.1.apk

0.5.0 — cambium-0.5.0.apk

sha256

9ccbf226e18036a57e6f402f81a55c7be7dd1986703af7e0581084e0a4e6d182

size

18.8 MB

archs

android-arm64-v8a, android-x86_64

version code

14

apk cert sha256

9ea188efa9015f7e7f90e1888f586f527b2a0e8a6dcdb3991e41fb4f14eeefc6

download

cambium-0.5.0.apk

Showing the newest 4 asset descriptors; the full set is in /api/apps/da19f1cd…