Verifiable Credential Toolkit

Tools and Library for Verifiable Credential creation and signing.

CLI Tools

vc_signer (cargo default-run)

A CLI tool for signing Verifiable Credentials

Usage: vc_signer <COMMAND>

Commands:
  sign  Sign a verifiable credential
  help  Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Sign a verifiable credential

Usage: vc_signer sign [OPTIONS] --input-vc <INPUT_VC> --key <KEY>

Options:
  -i, --input-vc <INPUT_VC>      Path to the unsigned VC JSON file
  -k, --key <KEY>                Path to the private key file
  -o, --output-vc <OUTPUT_VC>    Path to save the signed VC [default: signed_output.json]
  -s, --schema <SCHEMA>          Optional schema file path for validation
  -u, --schema-url <SCHEMA_URL>  Optional schema URL for validation
  -h, --help                     Print help

generate_keys

Generates Ed25519 key pairs

Usage: generate_keys [OPTIONS]

Options:
  -o, --output <OUTPUT>  Output directory for the keys [default: .]
  -h, --help             Print help
  -V, --version          Print version

WASM Compilation and Usage in Client-side Javascript in the browser

You can compile the sign and verify functions for web based WASM like so:

wasm-pack build --target web

Tested with:

wasm-pack --version
wasm-pack 0.13.1

By default it will build in the pkg directory.

I have put an example usage of the WASM functionality in the browser inside the ./wasm_js_example_usage directory.

If you compile it inside that directory in a directory called pkg like so:

wasm-pack build --target web --out-dir wasm_js_example_usage/pkg

Then run the web server at localhost 8080 with:

python3 -m http.server 8080

When you load the page in a browser and open the console you should see the signed VC object being logged and the successful result of the verification. See screenshot below:

The load_keys.mjs Node.js script can be used to print a private and public key to the command line in a format which can be copied into the index.js file for testing/example usage purposes.

WASM Compilation and Usage in Node.js

You can compile the sign and verify functions for nodejs based WASM like so:

wasm-pack build --target nodejs

I have put an example usage of the WASM functionality in a node script inside the ./wasm_nodejs_example_usage directory.

If you compile it inside that directory in a directory called pkg like so:

wasm-pack build --target nodejs --out-dir wasm_nodejs_example_usage/pkg

Then run the node script like so:

node index.js

It should log your VC to the console and the result of verification like so:

Signed VC: Map(6) {
'@context' => [ 'https://www.w3.org/2018/credentials/v1' ],
'id' => 'http://example.com/credentials/3732',
'type' => 'VerifiableCredential',
'issuer' => 'https://example.com/issuers/14',
'credentialSubject' => Map(1) { 'id' => 'did:example:abcdef' },
'proof' => {
type: 'Ed25519Signature2018',
proofPurpose: 'assertionMethod',
verificationMethod: undefined,
cryptosuite: 'eddsa-rdfc-2022',
created: '2025-02-27T10:17:09.806Z',
proofValue: 'ShO0cQNI3whBuwYNh2EDY3Mua/NLpu5n5QlC5vLQCv4aya5/vQI64avSZ2JcQOpUCf1SPQtzMDeurHNka8CmBA=='
 }
}
Verification result: true