Blockchain technology is becoming a ground-breaking system for safe, decentralized transactions in a variety of industries. Assuring transaction integrity, validity, and non-repudiation is still a difficult task, nevertheless, particularly in settings vulnerable to hostile assaults. The architecture for private key cryptography presented in this study is intended to improve digital signature authentication to safeguard blockchain networks. The suggested framework creates a safe and effective way to verify the legitimacy of digital signatures by utilizing the fundamental advantages of private key cryptography. The framework employs a strong cryptographic structure to guarantee data integrity, secrecy, and resistance against manipulation. This research illustrates the efficacy of the architecture in minimizing common vulnerabilities including replay attacks, man-in-the-middle attacks, and key exposure through thorough security analysis and performance rating.