Enrollment token while registering user

[Vishva066]

I am trying to use the Fabric CA Server API. In which it is requesting for enrollment token as a authorisation. How to generate this enrollment token. I tried the following steps:

1. Took the signcert of the identity which was bootstraped and converted to base64.
2. Then created a request.json which includes the body of the request which I am going to register.
3. Then took the sign cert and request.json along with the private key of the bootstraped identity and created a signature using this command.
   cat cert.pem request_body.json | openssl dgst -sha256 -sign priv_sk | base64 | tr -d '\n'
4. THen joined the base64 enrollment certificate and base64 signature using dot(.)
5. But got an error "Invalid token in authorization header: Failed to decode base64 encoded x509 cert: illegal base64 data at input byte 6"

Is these steps correct what is the correct flow here ???