npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@foxy.io/google-pay-decrypt

v1.0.1

Published

This package allows you to decrypt a token received from Google Pay.

Downloads

115

Readme

Google Pay Decrypt

This package allows you to decrypt a token received from Google Pay.

This works in node and not on a browser, as it requires the built-in crypto package and secret keys (.pem files), which should never exist on the client anyway.

The decryption methodology of this package is largely taken from the Python Google Pay Token Decryption.

Getting Started

npm i foxy-node-google-pay-decrypt

In order to decrypt the token, you will need the .pem file, the gateway id, and Google signing keys. In order to get the Google signing keys you will have to fetch them from one of the two URLs. You have the sandbox URL https://payments.developers.google.com/paymentmethodtoken/test/keys.json or the production URL https://payments.developers.google.com/paymentmethodtoken/keys.json.

And a key (privatePem.pem) that looks something like this:

-----BEGIN EC PRIVATE KEY-----
7G3PLjvRkmLcZd1H4CX6XbE7nrMrUU4tJc1sO5Cs0n4gnncYbJoTJXLIYN3o4FXL
9T33p5TtiTh4pkBzsj8zRHWeFrJoRaitZmnVBAL5u2v9f98d8mwN4uhP5bsS7lwa
GQPYeVaMGHaWQctQbQx26D1C5oGcPir3LP==
-----END EC PRIVATE KEY-----

Usage

The token that you get from Google Pay will look something like this:

{
    "signature": "MEYCIQD...<a lot more data>...9GwgIhALJ/5PrBogdma+aft/ZEU0UYklTEteJYrkbphfeg4FpW",
    "intermediateSigningKey": {
        "signedKey": "{\"keyValue\":\"MFkwEwYHKoZIzj0CAQYIKoZIzj0D...<a lot more data>...Qn1GLn9rh33FVdUadzkZc2b4oTCKA\\u003d\\u003d\",\"keyExpiration\":\"1698424300849\"}",
        "signatures": [
            "MEQCIAmx8FHGQs9jRTlacoUSD7T969Vz77+...<a lot more data>...mWh5f8qds+K6e+kL4wxdi/FswUQ=="
        ]
    },
    "protocolVersion": "ECv2",
    "signedMessage": "{\"encryptedMessage\":\"zA3SNtOdi...<a lot more data>...FhfKXNjcxz1LkEvTFKir8NFyoLf+Gbxcf7u3eNllgGwiTbjm1FlJAZHHy6WiNg\\u003d\",\"ephemeralPublicKey\":\"BDDaWyJv0u9DdWWosdYI...<a lot more data>...D8qntQO/3jhrMemajE4pI\\u003d\",\"tag\":\"lfEFA5...<a lot more data>...2bRGyS+yESzrqQ0\\u003d\"}"
}

To decrypt the token, import the .pem file, fetch the Google singing keys and create a new GooglePaymentToken with the token from Google Pay. Then decrypt using the keys.

const use_sandbox = false;
const rootSigningKeysUrl = use_sandbox ? 'https://payments.developers.google.com/paymentmethodtoken/test/keys.json' : 'https://payments.developers.google.com/paymentmethodtoken/keys.json';
fetch(rootSigningKeysUrl).then(async (result) => {
    const key = file.readFileSync('/path/to/key.pem');
    const rootSigningKeys = await result.json();
    const token = new GooglePaymentToken(rootSigningKeys.keys, 'gatewayId', key);
    const decryptedToken = token.decrypt(data);
    console.log(decryptedToken);
}).catch((err) => {
    console.log(err);
});

The decrypted value at this point should look something like this:

{
  messageExpiration: '169832356723',
  messageId: 'GQPYeVaMGHaWQctQbQx26D1C5oGcPir3LPGQPYeVaMGHaWQctQbQx26D1C5oGcPir3LPGQPYeVaMGHaWQctQbQx26D1C5oGcPir3LPGQPYeVaMGHaWQctQbQx26D1C5oGcPir3LPGQPYeVaMGHaWQctQbQx26D1C5oGcPir3LP',
  paymentMethod: 'CARD',
  paymentMethodDetails: {
    expirationYear: 2028,
    expirationMonth: 8,
    pan: '4111111111111111',
    authMethod: 'PAN_ONLY'
  }
}

You can then use those decrypted values with your payment processor of choice (Stripe, Braintree, et al) to process payments from Google Pay.