Looking for JWT Token and WEB API expert to modify the JWT Token payload without changing the signature

I need a skilled freelancer who can update the user identification information within JWT Tokens. The tokens already exist, so your task will include:

- **Understanding JWT**: You should be comfortable working with JSON Web Tokens and understand their structure.
- **Updating Payload**: Specifically, you'll update the existing payload with new user identification information provided as a JSON object.
- **Maintaining Integrity**: The crucial part of the task is to ensure that the signature remains intact and the token stays secure during and after modification.

**Ideal Skills and Experience**:
- Proven experience with Web APIs and JWT
- Familiarity with JSON data handling
- Knowledge of authentication and token-based security protocols
- Excellent attention to detail to ensure security standards are met

I look forward to collaborating with a professional who is confident in their ability to handle JWTs securely and efficiently.