Blackboard Logo

Security and Tokens

Blackboard Collaborate relies on JSON web tokens (JWT) to authenticate and authorize incoming REST API calls. A JSON web token can be signed with either RSA or HMAC. RSA allows the REST Client to sign the JWT with public and private keys via x.509 certificates. HMAC allows the JWT to be signed with a shared secret. Either way, the data can be trusted because it’s digitally signed with mutually known credentials.

Here’s a sample Python script that uses a correctly formed JWT assertion to request an access token and then uses the access token to make a single API request.

JWT Assertion

To get API access to Blackboard Collaborate, you must create a JWT assertion. A JWT assertion is a JSON web token request for access. It includes:

The header and payload are each base64 encoded and the three parts are separated with a dot, resulting in a token in this format:

encodedheader.encodedpayload.signature

and resembles the following:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJteS1jb2xsYWItcmVzdC1r
ZXkiLCJzdWIiOiJteS1jb2xsYWItcmVzdC1rZXkiLCJleHAiOiIxNDgwNDU3NzYzOTg4I
n0.7eElTSzDRfWaQlKeVaMDJlN07-_dmNq7nRP82pm47kY

JWT Header

The header is a JSON object with that identifies the algorithm used to generate the signature and the type of token being created. In this example, the application is signing the data with HMAC-SHA 256 and requesting a JSON Web Token.

{
  "alg": "HS256",
  "typ": "JWT"
}

To create the encodedheader part of the token, base64 encode this JSON.

JWT Payload

The payload contains information about the calling application that uniquely identifies the client to the REST server. Blackboard Collaborate REST APIs require these pieces of information:

For example:

{
  "iss": "my-collab-rest-key",
  "sub": "my-collab-rest-key",
  "exp": "1480457763988"
}

Base64 encode the payload and append it to the based64-encoded header, separated by a dot.

JWT Signature

The signature is basically the string created above (encodedheader.encodedpayload), signed using the algorithm specified in the header and the REST API secret provided by Blackboard. The resulting string must be appended to encodedheader.encodedpayload, separated with a dot.

Building a JWT Request

To request an access, you must make a POST request to the Collaborate API /token endpoint, like the following:

POST /token?grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&assertion=eyJhbGciOiJIUzI1NiIsIn
R5cCI6IkpXVCJ9.eyJpc3MiOiJteS1jb2xsYWItcmVzdC1rZXkiLCJzdWIiOiJteS1jb2xsYWItcmVzdC1rZXkiLCJleHAiOiIx
NDgwNDU3NzYzOTg4In0.7eElTSzDRfWaQlKeVaMDJlN0-_7dmNq7nRP82pm47kY

Also note:

Using the JWT Token

A properly formed POST to /token returns an access token. To authorize a request to Collaborate, add this access token as a Bear token in your request’s authorization header. The authorization header will look like the following.

    Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE0ODAzNzM2ODEsInN1YiI6ImJiQ29sbGFiQXBpIiwiaXNzIj
    oiYmJDb2xsYWJBcGkiLCJ0eXBlIjoxLCJjb25zdW1lciI6IjkxRjA1RENEODhGQzQzRkMwMUY0NjI5MDEwQzNFQjc3IiwiaWF0Ijo
    xNDgwMzczMzIxfQ.Vi7jejTo380R_DYWO202q3dvd0XYsQbmpFd3DCgku64

Additional Resources

JSON Web Tokens are a widely adopted standard in modern applications, and thus, there are a ton of resources available for developers interested in JWT beyond the scope of Blackboard Collaborate.