Malformed token error with base64 encoded secret

Start at the JWT verification API and reproduce the HS256 case using Buffer.from(process.env.JWT_KEY, 'base64') with the supplied token and secret. Determine the expected handling of the decoded secret, then add coverage for this reproduction and confirm that verification no longer reports a malformed token.

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Description

Using a base64 encoded secret with an HS256 token generates a Malformed token error. A full output of the error is as follows:

app_1  | Error: Malformed token
app_1  |     at /usr/src/app/.build/src/auth/authController.js:54:27
app_1  |     at step (/usr/src/app/.build/src/auth/authController.js:33:23)
app_1  |     at Object.next (/usr/src/app/.build/src/auth/authController.js:14:53)
app_1  |     at /usr/src/app/.build/src/auth/authController.js:8:71
app_1  |     at new Promise (<anonymous>)
app_1  |     at __awaiter (/usr/src/app/.build/src/auth/authController.js:4:12)
app_1  |     at exports.handler (/usr/src/app/.build/src/auth/authController.js:47:45)
app_1  |     at InProcessRunner.run (/usr/src/app/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/InProcessRunner.js:190:16)
app_1  |     at processTicksAndRejections (internal/process/task_queues.js:97:5)
app_1  |     at async LambdaFunction.runHandler (/usr/src/app/node_modules/serverless-offline/dist/lambda/LambdaFunction.js:355:20)
app_1  |     at async Object.authenticate (/usr/src/app/node_modules/serverless-offline/dist/events/http/createAuthScheme.js:101:24)
app_1  |     at async module.exports.internals.Manager.execute (/usr/src/app/node_modules/@hapi/hapi/lib/toolkit.js:45:28)
app_1  |     at async module.exports.internals.Auth._authenticate (/usr/src/app/node_modules/@hapi/hapi/lib/auth.js:256:30)
app_1  |     at async Request._lifecycle (/usr/src/app/node_modules/@hapi/hapi/lib/request.js:312:32)
app_1  |     at async Request._execute (/usr/src/app/node_modules/@hapi/hapi/lib/request.js:221:9)
app_1  | offline: Authorization function returned an error response: (λ: auth)

Reproduction

1. Generate a token and key from here: https://java.jsonwebtoken.io/ or https://jwt.io and set the secret to base64 encoded
2. Add the secret key to your project.
3. Pass a request with the generated JWT and watch it error out. Code as follows:

      const valid = jwt.verify(
        token,
        Buffer.from(process.env.JWT_KEY, 'base64'),
        { algorithms: ['HS256'] }
      )

Environment

Please provide the following:

• Version of this library used: 8.5.1
• Version of the platform or framework used, if applicable:
• Other relevant versions (language, server software, OS, browser): I'm using serverless-offline. This is a Lambda-based API
• Other modules/plugins/libraries that might be involved: While I was able to re-create this using both java.jsonwebtoken.io and jwt.io I was also able to recreate the issue using tokens and keys directly using JJWT in Springboot. Note: the generated secret and token does work from any of these sources when using it within the Springboot API. Also of note is that this is all running in Docker. Also of note if I generate a token from jwt.io w/out base64 encoding the key then this will work fine (w/out Buffer obviously).