# Doctrina: Blockchain 5.0 for Artificial Intelligence
## 4 Doctrina
### Roles of Public Network  
The public network within Doctrina's blockchain framework plays a crucial role in maintaining transparency, security, and trust among its users. It serves the following several key functions:  
* Transaction confirmation: Every transaction on Doctrina, whether it is related to the deployment of an AI service, model updates, or other operations, requires validation. The public network is responsible for confirming these transactions through a consensus mechanism. This process ensures that once transactions are verified and added  
Figure 4: Block tail metadata.  
Figure 3: Doctrina block indexing.  
to the blockchain, they are immutable and cannot be altered, creating a secure and tamper-proof record.
* Auditing: The public network allows for full traceability of transactions and AI services execution. This enables any stakeholder to audit the history and integrity of the AI services and their associated transactions. Auditing is critical for accountability and is useful for regulatory compliance, especially in fields where AI decisions must be explainable and transparent.
* Decentralization of trust: By allowing a broader public network to participate in the transaction validation process, trust is distributed among many nodes rather than being concentrated in a single entity. This decentralized approach to trust is fundamental to blockchain technology and helps prevent single points of failure.
* Security: The public network contributes to the overall security of the blockchain. The larger and more distributed the network, the more secure it is against attacks, such as the 51% attack, where a user or group gains control of the majority of the network's mining power to manipulate the blockchain.
* Incentive mechanism: Participants in the public network, often called validators or miners, may receive incentives or rewards for their role in confirming transactions and maintaining the blockchain. This incentivization ensures that there is always a sufficient number of participants to keep the network functional and secure.
* Public verification: For AI services that impact public domains or require public trust, having a public network that verifies the operations of these services can provide a layer of assurance to external observers that the AI's actions are consistent and based on unaltered data.  
In summary, the public network in Doctrina serves as the backbone for ensuring that the blockchain operates in a transparent, secure, and reliable manner, which is especially important when it comes to the execution of AI services where outcomes must be verifiable and trustworthy.  
Doctrina presents a fundamentally new approach to integrating artificial intelligence directly into blockchain infrastructure by enabling AI models to run natively on-chain. Unlike existing architectures that rely heavily on off-chain computation or third-party services to process AI tasks, Doctrina allows AI models to be deployed, executed, and verified entirely within the blockchain environment. This ensures full transparency, immutability, and trust in AI-driven operations. Doctrina achieves this through a combination of smart contract extensions for handling AI-specific logic, an optimized execution environment that supports efficient computation, and a verification system that ensures model outputs are reproducible and tamper-proof. Additionally, Doctrina includes decentralized governance mechanisms for managing model updates and data validation, making it possible to build autonomous, community-driven AI services without centralized control. These features collectively distinguish Doctrina from existing approaches and represent a significant step toward intelligent and secure decentralized ecosystems.