First, you will need to generate a private and public key-pair. You can do so using the following commands:

# Private Key
openssl genrsa -out private-key-name.pem 3072
# Public Key
openssl rsa -in private-key-name.pem -pubout -out public-key-name.pem

You can customize the key to better suit your needs, but keep in mind you'll have to modify the settings in the keyConfig constant in the /utils/rsa.ts file.

Then you will need to set the keys into environment files. The private key goes to the backend, and the public key goes to the frontend.

In this project, you can duplicate the .env.local.example file and rename it to .env.local.

In your env files, use double-quotes around the variable's value to support the \n character, place a \n at the end of each line, and then reduce the whole key into a single line, like so:

-----BEGIN RSA PRIVATE KEY-----\nFiRsTlInE\nSeCoNdLiNe\nThIrDlInE\nSoOnAnDSoFoRtH\n-----END RSA PRIVATE KEY-----

There is an .env.local.example file with an example to help you understand, along with an example pair of keys.

Finally, run the development server:

npm run dev
# or
yarn dev
# or
pnpm dev

Open http://localhost:3000 with your browser to see the result.

If you see the name John Doe, the signature and verification worked properly. If you try to modify this data after it was signed, or before it is verified, an error will appear.