PGP Signing Plugin

The PGP signing plugin enables Vultrino to store PGP private keys and perform cryptographic signing operations.

Installation

vultrino plugin install https://github.com/vultrino/plugin-pgp

Or build from source:

cd plugins/pgp-signing
cargo build --release --target wasm32-wasip1
vultrino plugin install ./plugins/pgp-signing

Credential Type: pgp_key

Store a PGP private key in Vultrino.

Fields

Field	Type	Required	Description
`private_key`	textarea	Yes	ASCII-armored PGP private key
`passphrase`	password	No	Passphrase to unlock the key
`key_id`	text	No	Specific key ID to use

Adding via CLI

vultrino add --alias my-pgp-key --type plugin:pgp-signing:pgp_key
# You will be prompted for the private key and passphrase

Adding via Web UI

Navigate to Credentials > Add Credential
Select “PGP/GPG Key (pgp-signing)” from the dropdown
Paste your ASCII-armored private key
Enter passphrase if the key is encrypted
Click “Add Credential”

Available Actions

sign

Create a signature for arbitrary data. Returns a base64-encoded signature.

Parameters:

data (string, required) — Data to sign
armor (boolean, optional) — Output armored format (default: true)

sign_cleartext

Create a PGP cleartext signed message. The message text is visible, with the signature appended.

Parameters:

message (string, required) — Message to sign

Example output:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Your message here
-----BEGIN PGP SIGNATURE-----

iQIzBAEBCAAdFiEE...
-----END PGP SIGNATURE-----

verify

Verify a cleartext signed message.

Parameters:

data (string, required) — Original data that was signed
signature (string, required) — The cleartext signed message

Returns: "true" or "false"

get_public_key

Extract the public key from the stored private key.

Parameters:

armor (boolean, optional) — Output armored format (default: true)

MCP Tools

When running with MCP enabled, these tools are available:

Tool	Description
`pgp_sign`	Sign data and return the signature
`pgp_sign_cleartext`	Create a cleartext signed message
`pgp_verify`	Verify a signature
`pgp_get_public_key`	Get the public key

Example MCP Usage

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "pgp_sign_cleartext",
    "arguments": {
      "credential": "my-pgp-key",
      "message": "I agree to these terms."
    }
  }
}

Use Cases

Git Commit Signing

Use with AI agents to sign commits:

# Configure git to use Vultrino for signing
git config --global gpg.program vultrino-gpg-wrapper

Document Signing

Create verifiable signatures on documents:

vultrino request my-pgp-key --action sign_cleartext \
  --param message="I approve this document"

Key Management

Securely store team PGP keys without exposing private key material:

Store the private key in Vultrino
Create API keys for team members
Team members can request signatures without accessing the key

Security Considerations

Private keys are encrypted at rest using AES-256-GCM
Keys are only decrypted in memory during signing operations
The WASM sandbox isolates plugin execution
Audit logs track all signing operations

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