What is a Hash?

Discover the role of hashes in eDiscovery, enhancing data integrity, simplifying document review through de-duplication, and ensuring the authenticity of evidence.

Hashes play a pivotal role in the realm of electronic discovery (eDiscovery), where they serve as essential tools for identifying, collecting, and producing electronically stored information (ESI) in legal proceedings. By offering a reliable means to verify the integrity and authenticity of digital documents, hashes significantly enhance the efficiency and accuracy of the eDiscovery process. This article expands on the basics of hash functions, focusing particularly on their utility in eDiscovery.

Hash Functions in eDiscovery

In the context of eDiscovery, hash values are utilized to uniquely identify and manage documents. Here's how they contribute to various stages of the eDiscovery process:

A screenshot of sha512 checksum hashes.

Data Identification and Collection

When identifying and collecting ESI for a legal case, it's crucial to ensure that the data remains unchanged from its original state. Hashes provide a digital fingerprint for each file, enabling legal teams to verify that the documents collected are identical to those initially identified, without alterations.


One of the most significant advantages of using hash functions in eDiscovery is their ability to streamline the review process through de-duplication. By generating hash values for all documents, identical files can be easily identified and removed from the dataset. This process not only reduces the volume of data to be reviewed but also minimizes the risk of inconsistencies in document handling and analysis.

Integrity and Authenticity Verification

Throughout the eDiscovery process, maintaining the integrity and authenticity of ESI is paramount. Hashes ensure that documents have not been tampered with or altered since their collection. Before analysis, a document's hash value can be compared to its original hash to confirm its integrity. This step is crucial in legal contexts, where the admissibility of evidence can hinge on its unaltered state.

Chain of Custody Documentation

Maintaining a documented chain of custody for ESI is essential in legal proceedings to demonstrate the control, transfer, analysis, and disposition of evidence. Hash values aid in creating an immutable record of each document's journey through the eDiscovery process. By logging the hash values at each stage, legal teams can provide concrete evidence of the data's authenticity and integrity, reinforcing the credibility of the evidence.

Challenges and Best Practices

Despite their utility, the application of hash functions in eDiscovery faces challenges, particularly concerning the handling of dynamic and complex data types, like emails or databases, where minor changes can alter hash values. Addressing these challenges requires a nuanced understanding of hash function properties and the selection of appropriate algorithms for different data types.

To maximize the benefits of hashes in eDiscovery, legal and IT professionals should adhere to best practices, including:

  • Choosing Robust Hash Algorithms: Opt for secure and widely accepted hash algorithms, such as SHA-256, to ensure reliability and resistance against collisions.
  • Comprehensive Documentation: Maintain detailed records of hash values and the corresponding stages in the eDiscovery process to support the evidence's integrity and authenticity.
  • Regularly Update Security Protocols: Stay informed about developments in cryptographic security and update eDiscovery practices accordingly to mitigate risks associated with hash function vulnerabilities.


Hash functions are indispensable in the eDiscovery process, offering a methodical approach to data identification, de-duplication, verification, and documentation. By ensuring the integrity, authenticity, and efficient management of electronically stored information, hashes greatly contribute to the accuracy and reliability of legal evidence. As digital data continues to grow in volume and complexity, the role of hash functions in eDiscovery is set to become even more critical, underscoring the importance of understanding their application and best practices in legal contexts.

Photo by Immo Wegmann on Unsplash

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