When stealing and selling digital information for illegal profit, criminals may use the following technical strategies: 1. **Phishing**: Using fake websites or emails to trick users into entering sensitive information such as usernames, passwords, and credit card information. 2. **Malware**: Using malicious programs such as viruses, Trojans, and spyware to infect users' devices to steal data or monitor user behavior. 3. **Social Engineering**: Manipulating the psychology of individuals or organizations to obtain sensitive information through phone calls, social media, or face-to-face communication. 4. **Data mining and crawler technology**: Using crawlers to automatically extract data from websites, which may include user information, transaction records, etc. 5. **Network vulnerability exploitation**: Taking advantage of security vulnerabilities in software or systems to directly attack the target system and obtain sensitive information. 6. **Man-in-the-middle attack**: Inserting oneself between users and services to intercept transmitted data, such as login credentials and personal information. 7. **Encrypted information theft**: Obtaining users' encryption keys through various means to decrypt and obtain sensitive data. 8. **Cloud storage attack**: Attacking personal or corporate data stored in the cloud and infiltrating using insecure interfaces or configuration errors. 9. **Social media monitoring**: Obtaining users’ personal information through monitoring social media platforms to conduct identity theft or social engineering attacks. The use of these technical strategies not only involves legal issues, but also involves ethical and social responsibilities. Organizations and individuals should take appropriate security measures to prevent these threats.