I. Introduction  
II. Preliminaries  
A. Definition of Technical Terms  
B. Classical Scenarios and Corresponding Capacities  
III. Poisoning-Based Backdoor Attacks  
A. A Unified Framework of Poisoning-based Attacks  
B. Evaluation Metrics  
C. Attacks for Image and Video Classification  
D. Attacks against Other Fields or Paradigms  
E. Backdoor Attacks for Positive Purposes  
IV. Non-Poisoning-Based Backdoor Attacks  
A. Weights-oriented Backdoor Attacks  
B. Structure-modified Backdoor Attacks  
V. Connection with Related Realms  
A. Backdoor Attacks and Adversarial Attacks  
B. Backdoor Attacks and Data Poisoning  
VI. Backdoor Defenses  
A. Empirical Backdoor Defenses  
B. Certified Backdoor Defenses  
C. Evaluation Metrics  
VII. Benchmark Datasets  
VIII. Outlook of Future Directions  
IX. Conclusion