Example C++ Cryptographic Verification

This is an example of cryptographically verifying a license key's authenticity, and extracting embedded tamper-proof data within the key for offline use, all by using your Keygen account's public key. This example implements the ED25519_SIGN scheme. For an RSA example, check out this repo.

Cryptographically verifying schemed licenses can be used to implement offline licensing, as well as to add additional security measures to your licensing model. All that is needed to cryptographically verify a license is your account's public key.

You can find your Ed25519 public key within your account's settings page.

Running the example

First up, add an environment variable containing your public key:

# Your Keygen account's Ed25519 public key
export KEYGEN_PUBLIC_KEY='e8601e48b69383ba520245fd07971e983d06d22c4257cfd82304601479cee788'

You can either run each line above within your terminal session before starting the app, or you can add the above contents to your ~/.bashrc file and then run source ~/.bashrc after saving the file.

On macOS, compile the source using g++:

g++ main.cpp -o bin.out -std=c++17 -stdlib=libc++ -I include/**/*.c

Then run the script, passing in the key as the first argument:

./bin.out 'key/signed.key'

Alternatively, you can prefix the below command with env variables, e.g.:

KEYGEN_PUBLIC_KEY=... ./bin.out 'key/...'

The license key's signature will be verified using Ed25519.

You can find your public key in your settings.

Running on other platforms

We are only including instructions on how to compile and run this example on macOS. If you'd like to create a PR with instructions for another platform, such as Windows or Linux, please feel free to open a PR.

If you have any tips on how to improve the compilation, please open a PR.

Questions?

Reach out at support@keygen.sh if you have any questions or concerns!