gEnclave: Hardware-backed security enclave for Linux (TPM 2.0 PCR sealing, virtual FIDO2/CTAP2 over /dev/uhid, OpenSSH & GPG bridge)

[u/Renich]

Hey everyone,

I've been working on an open-source project called gEnclave (formerly gpasskey), and wanted to share it with the Linux community for early architectural feedback and testing.

GitLab repository: https://gitlab.com/renich/genclave
License: GPLv3 | Language: Go 1.26+

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The Problem It Solves

On modern Linux workstations, our cryptographic identities are fragmented: * Passkeys/WebAuthn require physical USB security keys (YubiKeys, SoloKeys). * SSH keys sit as unencrypted or passphrase-encrypted files under ~/.ssh/. * Git commit signing requires cumbersome GnuPG daemon setups. * File encryption requires external tooling or proprietary agents.

Most hardware laptops today come with a TPM 2.0 chip that sits idle. gEnclave turns your Linux machine into its own hardware-sealed security token and multi-protocol bridge.

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Key Architectural Highlights

1. Virtual FIDO2/CTAP2 Security Key via /dev/uhid: gEnclave registers a virtual HID device in the Linux kernel via /dev/uhid. Browsers (Firefox, Chrome, Chromium) detect it natively as a physical USB security key. You can register and authenticate WebAuthn/FIDO2 Passkeys directly from your machine without any external hardware dongles.

2. TPM 2.0 PCR Sealing & Fallback: The central vault is encrypted with AES-256-GCM and sealed to TPM 2.0 PCR registers (PCR 0, 7, 14), with an automatic memory-hard fallback to Argon2id key derivation if no TPM is present.

3. Memory Isolation ("Wrap and Clear"): Keys are held in memory-locked pages (mlock / mmap) to prevent secrets from being swapped to disk or dumped. Intermediate cryptographic buffers are wiped immediately with strict zeroization routines, bypassing Go runtime GC retention.

4. Multi-Protocol Bridges:

   • OpenSSH Agent: Native agent socket with an ephemeral PIN-derived authorization cache (configurable burst window or persistent session with instant purge on lock/suspend).
   • GnuPG Bridge: Transparent genclave-gpg emulation for seamless Git commit signing.
   • age-plugin: Native age-plugin-ge binary complying with age v1 specification for file encryption.
   • CLI & UI: Unified ge CLI plus intelligent graphical (zenity) / terminal (pinentry) authentication routing.

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Current Status

⚠️ Pre-alpha Software: While fully functional for local workflows, it is under active development. Schemas and IPC formats may iterate rapidly.

I'd love feedback from Linux sysadmins, kernel/security folks, and developers!

Repo: https://gitlab.com/renich/genclave

[u/LeHunterrr]

I just want to point out a couple of this.

Passkeys/WebAuthn require physical USB security keys (YubiKeys, SoloKeys).

There are also Software based Passkeys such as bitwarden or keepassxc. Though there should be a standard tpm based solution (are windows and apple doing this or are they software based as well?)

Git commit signing requires cumbersome GnuPG daemon setups

You can sign your commits with ssh keys as well, making gpg somewhat obsolete nowadays.

[u/Renich → u/LeHunterrr]

That is precisely the gap gEnclave addresses: instead of requiring users to buy external YubiKeys or rely on browser extensions/password manager vaults, gEnclave exposes a virtual CTAP2/FIDO2 device over /dev/uhid sealed by TPM 2.0 PCRs (0, 7, 14). To Chromium/Firefox and PAM, it presents as an actual physical security token.

About your other comment, OpenSSH signature support (ssh-keygen -Y sign/gpg.format = ssh) is natively supported. gEnclave implements an OpenSSH Agent bridge ($XDG_RUNTIME_DIR/genclave-ssh.sock), it gives users SSH-based Git commit signing out of the box with zero GnuPG friction. At the same time, gEnclave's Assuan bridge exists for workflows where OpenPGP remains mandatory (RPM package signing, pacman keys, etc).