The expansion of digital transactions and the increasing use of blockchain-based technology pose challenges to the ability of Indonesia's civil law system to provide stable and predictable legal certainty. This article examines the compatibility of smart contracts and digital notary authentication with the principle of legal certainty, particularly within the normative structure of the Civil Code, the Electronic Information and Transactions Law (UU ITE), and the Notary Law (UUJN). The study uses a normative juridical method with statutory, conceptual, and comparative approaches to assess regulatory coherence, test the adequacy of the doctrine of contract formation, and analyze the repositioning of notary functions when projected into a digital system. Data were obtained through a literature review of national regulations, international standards on digital identity and electronic signatures, blockchain-related academic literature, and the practices of civil law countries such as France and Estonia. The analysis was conducted through systematic interpretation and doctrinal mapping to identify normative gaps, conceptual conflicts, and regulatory inconsistencies. The study results indicate that the Indonesian legal framework is unable to provide adequate mechanisms for defining intent in code-based agreements, determining responsibility for algorithmic actions, or establishing standards of proof for immutable ledger data. On the other hand, the formal structure of authentic deeds in the UUJN limits the possibility of recognizing digital deeds without explicit legislative reform. The novelty of this research lies in the formulation of an integrated legal model that aligns smart contract execution, digital authentication, and notary authority within a single framework of legal certainty, and demonstrates that predictability can only be achieved through the codification of technical standards, digital verification procedures, and oversight mechanisms appropriate to the characteristics of distributed ledger technology.