Setting up the id_token

A JWT (Json Web Token) has to be generated to be added to the Token URL which would be of the format :

${redirect_uri}?state=${state}&id_token=${jwt_token}`

Problem Statement

How to generate the token?

Resolution Path

A JWT typically has three parts in form xxx.yyy.zzz where :

• xxx = Header 

The header typically consists of two parts: the type of the token, which is JWT, and the signing algorithm being used, in case of Freshworks, it is RS256. Here's a sample

{ "alg": "RS256", "typ": "JWT"} 

Then, this JSON is Base64Url encoded to form the first part of the JWT.

• yyy= Payload

The payload contains the data related to the identity along with secure parameters exchanged in JSON format. For example,

{     "sub": "1234567890",     "email": "messi@awesomecompany.com",     "nonce": "123422" } 

The payload is then Base64Url encoded to form the second part of the JSON Web Token.

• zzz=To create the signature part you have to take the encoded header, the encoded payload, RSA private key, and sign that. You can generate the RSA Key using the following script

  #generate RSA key ssh-keygen -t rsa -b 1024 -m PEM -f jwtRS256.key # use empty passphrase openssl rsa -in jwtRS256.key -pubout -outform PEM -out jwtRS256.key.pub 

  Or use the online generators Link1, Link2

Putting it all together, a sample JWT token looks like this

eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.TCYt5XsITJX1CxPCT8yAV-TVkIEq_PbChOMqsLfRoPsnsgw5WEuts01mq-pQy7UJiN5mgRxD-WUcX16dUEMGlv50aqzpqh4Qktb3rk-BuQy72IFLOqV0G_zS245-kronKb78cPN25DGlcTwLtjPAYuNzVBAh4vGHSrQyHUdBBPM

These are the parameters that may be passed in the payload.