Blockchain technology has surfaced as a transformative force in various sectors, delivering new levels of security, transparency, and efficiency. In Artificial Intelligence (AI) systems, blockchain technology shines as a remarkable solution to some of the biggest security challenges.

Blockchain is a type of distributed ledger technology, with transactions, recordings, or interactions securely logged and verified across a network of members instead of a single central authority. This decentralized format offers many advantages when employed for AI security.

• Decentralization
  Since information isn't held at a single point but distributed across nodes, eliminating a central point of vulnerability makes the system highly resistant to common cyber threats or data breaches.

• Transparency and Traceability
  Every transaction or interaction is timestamped and recorded across the distributed ledger, permitting complete traceability and transparency - imperative features in AI systems where system behavior accountability is necessary.

• Immutability

Once logged in a blockchain, data cannot be altered or deleted, a feature that is critical in preserving the integrity of AI systems, and ensuring that system training data hasn't been tampered with.

• Security
  Blockchain employs complex cryptographic processes making it virtually impossible for hackers to manipulate the data.

• Autonomy
  Smart contracts or programmable contracts established within the blockchain control transactions, reducing the need for intermediaries or manual oversight.

• Robust Security: Blockchain technology mitigates single-point vulnerabilities due to its decentralized architecture. The cryptographic algorithms ensure data integrity.
• Privacy Preservation: Blockchain can segregate personal data from AI computations, ensuring the AI can learn without compromising personal data.
• Transparency and Auditability: An immutable, time-stamped block holds every transaction, enabling full traceability.
• Reduced Needy for Trust: With transparency and immutability, Blockchain decreases the requirement of trust among parties.
• Lower Risk of Failure: As data is replicated across all nodes, the dependency on a single point reduces, lowering the risk of system failure.

• Scalability Challenge: The system can become slow and create hindrance to scalability as every node maintains a full copy of the chain.
• Energy-Consumption: Proof-of-Work (PoW) consensus mechanisms employed in Blockchain can lead to high energy consumption.
• Complexity: Implementing a blockchain solution introduces a level of complexity.
• Data Privacy: Complete transparency might not always be desirable.
• Integration Challenges: For existing AI systems, integration can be costly and complex.

The implementation of blockchain for AI security involves a careful evaluation, understanding the security vulnerabilities, pinpointing the areas where blockchain may provide significant advantages. There would be a need for selecting and designing the most suitable blockchain system, followed by a cost-benefit analysis.

The fusion of blockchain technology and AI could unchain the full potential of both technologies, creating AI systems that are not only intelligent but also secure and reliable. However, it requires strategic planning, careful implementation, and adaptability to overcome the associated challenges.