Hash Value: The Digital Fingerprint of Electronic Evidence

 Electronic evidence has become an integral part of modern trials. CCTV recordings, mobile-phone data, emails, WhatsApp messages, call recordings and digital documents can provide valuable assistance to the Court. However, such evidence is also vulnerable to alteration, manipulation and fabrication. In this context, a hash value serves as the digital fingerprint of an electronic file.

When a digital file is processed through a specified hash algorithm, a unique sequence of characters is generated. If the contents of the file are changed—even slightly—the resulting hash value will ordinarily change. The investigating agency, forensic laboratory and Court can therefore compare the hash value of the record originally preserved with that of the record subsequently produced. A matching hash value supports the conclusion that the file has remained unchanged.

The importance of this safeguard has been recognised under Section 63(4) of the Bharatiya Sakshya Adhiniyam, 2023. The statutory certificate requires disclosure of the hash value of the electronic record and also provides for expert certification. In Pune Bar Association v. Union of India, W.P. (C) No. 599 of 2026, decided on 22 May 2026, the Supreme Court upheld the constitutional validity of these requirements. The Court described the hash value as an “electronic fingerprint” which assists in identifying and verifying digital data and held that the requirement bears a rational nexus with the object of ensuring authenticity and integrity of electronic evidence.

The decision also makes clear that the certificate and hash-value requirements should not be treated as empty technical formalities. They constitute important safeguards intended to protect the reliability of electronic records. At the same time, the Court clarified that the expert required for Part B of the certificate need not necessarily be confined to a person notified under Section 79A of the Information Technology Act, 2000. A person possessing appropriate expertise in computer science or cyber forensics may qualify, subject to the satisfaction of the Court.

Nevertheless, a hash value has a limited evidentiary function. It establishes, or helps establish, the integrity of the digital file; it does not by itself prove the truth of every fact depicted or recorded in that file. A matching hash value does not establish that the person shown in a CCTV recording is the accused, that the camera clock was accurate, or that the recording faithfully represents the incident. Those matters require independent appreciation of the surrounding evidence.

Thus, the correct judicial approach is two-fold: first, to verify whether the electronic record has been preserved and produced in accordance with Section 63 of the Bharatiya Sakshya Adhiniyam; and second, to independently assess its authenticity, relevance, reliability and probative value. A hash value protects the record from unnoticed alteration, but it does not replace judicial evaluation of the evidence.

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