Blockchain adoption across financial, healthcare, and supply chain ecosystems has accelerated, yet deployed blockchain architectures remain susceptible to vulnerabilities in smart contract execution and intrusion threats. This research introduces an embedded validation framework for deployed blockchain architectures, leveraging cryptanalysis-enhanced smart contracts on Ethereum to strengthen network resilience. The proposed approach validates the operational integrity of existing blockchain deployments by embedding intrusion detection logic within Ethereum smart contracts, augmented with cryptanalytic techniques to uncover latent weaknesses in consensus, transaction validation, and contract execution. Unlike traditional off-chain security mechanisms, this framework operates natively within the blockchain layer, ensuring continuous, tamper-resistant validation of security states. An experimental evaluation of Ethereum-based networks demonstrates the framework’s capability to detect adversarial behaviors, cryptographic inconsistencies, and contract-level exploits while maintaining scalability and low overhead. The results highlight the potential of cryptanalysis-driven validation as a foundational step toward self-defending, secure blockchain infrastructures. This work bridges the gap between theoretical cryptanalysis and real-world blockchain validation, establishing a pathway for future research in autonomous and verifiable decentralized systems.