1. Introduction  
2. Security Challenges and Attacks in IoTs  
3. Physically Unclonable Functions (PUFs)  
4. PUF-based Security Solutions  
5. Fuzzy Extractors  
6. Generation of Cryptographic Keys from PUFs using Fuzzy Extractors  
7. Attacks on Fuzzy Extractors via Helper Data Manipulation  
8. Conclusion and Future Discussion  