Establishing a Legally Defensible Blockchain Chain of Custody Framework

Abstract

Blockchain technology offers significant potential for improving chain of custody procedures through immutable recordkeeping and transparent audit trails. However, existing research prioritizes technical innovation over legal compliance, proposing sophisticated systems without analyzing whether courts would admit blockchain-based custody records as evidence. This gap creates a fundamental barrier to practical adoption. This thesis establishes a legal baseline for blockchain chain of custody systems by analyzing Federal Rules of Evidence, expert testimony standards (Daubert and Frye), NIST guidelines, and relevant case law. The analysis reveals that legal admissibility depends less on technical sophistication than on demonstrable compliance with established standards. Systems incorporating novel cryptographic techniques and sophisticated softwares face higher evidentiary burdens under Daubert and Frye, while systems built from well-established components – SHA-256 hashing, RSA signatures, and Practical Byzantine Fault Tolerance consensus – can satisfy authentication requirements with minimal legal risk. This thesis presents a reference architecture that prioritizes legal defensibility over technical optimization, providing a foundation for future research. By deriving technical requirements from legal constraints rather than retrofitting legal justifications onto existing designs, this framework enables evaluation of whether proposed innovations enhance or compromise admissibility prospects. This legal baseline establishes minimum requirements that reduce evidentiary risk and provide a defensible starting point for pilot implementations that can accelerate practical adoption.