When it comes to information security, there are several reputable platforms that offer free courses to help you develop your knowledge and skills in this critical field. Here are some of the best free information security courses available online:

1. Cybrary: Cybrary offers a wide range of free online courses on various information security topics. Their course catalog includes introductory courses on cybersecurity, ethical hacking, network security, and more. They also provide advanced courses for individuals looking to deepen their knowledge in specific areas.

2. OpenSecurityTraining: OpenSecurityTraining is a community-driven platform that provides free and open-source training materials for information security. They offer a vast library of video lectures, tutorials, and resources covering topics such as reverse engineering, malware analysis, digital forensics, and secure coding practices.

3. SANS Cyber Aces Online: SANS Cyber Aces Online provides free introductory cybersecurity courses designed for beginners. These courses cover foundational concepts, including networking, operating systems, and systems administration. They also introduce learners to cybersecurity careers and provide insights into various roles within the industry.

4. National Initiative for Cybersecurity Careers and Studies (NICCS): NICCS offers free online training resources through their Training Catalog. They provide a wide range of courses on cybersecurity, risk management, incident response, and more. The catalog includes courses from various government agencies, universities, and private organizations.

5. Stanford University's Open Security Training: Stanford University's Open Security Training platform offers a collection of free, self-paced courses and training materials on a variety of information security topics. The courses cover subjects such as software exploitation, secure coding, cryptography, and web security.

6. University of Helsinki's Elements of AI: While not strictly focused on information security, the University of Helsinki's Elements of AI course provides a solid foundation in artificial intelligence. Understanding AI is crucial for information security professionals, as many security challenges arise in AI-driven systems. This course is available for free and can help you grasp the basics of AI and its security implications.

7. OWASP (Open Web Application Security Project): OWASP is a community-driven organization that focuses on web application security. They provide a vast amount of free resources, including training materials, documentation, and tools to enhance your understanding of web security and secure development practices.

Remember, while these free courses offer valuable knowledge, it's essential to practice your skills and keep up with the latest trends and threats in information security. Engage in hands-on exercises, participate in Capture the Flag (CTF) competitions, and join online security communities to deepen your understanding and gain practical experience.

By taking advantage of these free information security courses, you can lay a strong foundation and build your expertise in this critical field. Happy learning and best of luck in your information security journey!