Overview

“Proving the Integrity of Digital Evidence with Time” is a foundational article by Chet Hosmer (President and CEO of WetStone Technologies) published in the International Journal of Digital Evidence, Spring 2002, Volume 1, Issue 1. It argues that the existing integrity methods for digital evidence, checksums and digital signatures, bind identity and content but omit a trusted record of time. Hosmer proposes secure, auditable electronic timestamps traceable to Coordinated Universal Time (UTC) so that forensic investigators can prove not only who handled evidence and what it contained, but precisely when its integrity was protected. The paper frames the goal as binding the “who,” the “what,” and the “when” into a single durable integrity mark suitable for legal chain of custody.

Key points

• The core thesis is that proving digital evidence integrity requires three bound elements: identity (who, via the signer), content (what, via a hash), and time (when), and that time was the missing element in 2002 best practice.
• It reviews and critiques prior methods: checksums (CRC-16/CRC-32) are fast but offer low assurance against malicious attack; one-way hashes (MD2/MD4/MD5/SHA) detect malicious alteration but bind neither identity nor time; digital signatures (RSA/DSA/PGP) bind identity but still do not bind time and can be invalidated if keys are compromised or certificates expire.
• It defines digital integrity, citing the Handbook of Applied Cryptography, as the property that data has not been altered in an unauthorized manner since it was created, transmitted, or stored by an authorized source.
• It grounds trusted time in UTC, adopted by over forty countries running more than two hundred atomic clocks since 1972, and draws an analogy to notarization, which supplies an authoritative date, certifies it applies to the transaction, and can be verified by disinterested third parties.
• It specifies five attributes for secure, auditable date/time stamps: accuracy, authentication (traceable to a National Measurement Institute timing lab), integrity, non-repudiation, and accountability.
• It lays out a three-step architecture: traceability to legal UTC time sources, secure and auditable time distribution, and secure digital timestamping performed inside a trusted computing environment with routine third-party calibration and third-party-verifiable output.

Relevance to Truestamp

Hosmer’s who/what/when framing anticipates Truestamp’s separation of authorship, content hashing, and provable timing, and his emphasis on third-party-verifiable, tamper-evident time maps to the submission window that Truestamp proves rather than a claimed creation time. His argument that content and identity binding is incomplete without trusted time underpins Truestamp’s combination of hashing, Ed25519 signatures, and independently verifiable proofs, clarifying what Truestamp proves.

Citations

1. Proving the Integrity of Digital Evidence with Time. Chet Hosmer, WetStone Technologies, Inc.; International Journal of Digital Evidence, Spring 2002, Volume 1, Issue 1.