How Timestamps Protect Data Integrity For The Dubai Police

Published 13.3.2024

The Dubai Police demonstrated a Cardano-based pilot project focused on secure data management related to criminal investigations during the World Police Summit in Dubai. The use of blockchain guarantees that information is unaltered and makes it traceable for the different parties. This ensures the integrity of the data, which is crucial in criminal investigations where the accuracy of information can make or break a case. While the system’s operation specifics are not publicly available, we can provide an overview of how blockchain can safeguard data integrity. This article will explain how this process works, focusing on the role of hashing and timestamps.

How To Ensure Data Integrity

In the digital world, ensuring the integrity of data is paramount. One technology that has proven particularly effective in this regard is blockchain, which can be used as a kind of digital notary.

It is needed to have two interconnected systems working side by side:

  • Database: This is where your actual data or documents are stored. Databases are designed to store, retrieve, and manage data efficiently. They can handle large amounts of data and complex data structures like documents. However, while databases have mechanisms for ensuring data integrity, they can be vulnerable to tampering or alteration.
  • Blockchain: This is where the hashes of your data or documents are stored. The blockchain doesn’t store the actual data, but a unique hash of it. This hash acts like a digital fingerprint for your data. If the data changes, the hash changes. And because the blockchain is immutable (i.e., data once written cannot be changed), you have a tamper-proof record of the hash of your data.

The illustration depicts the integration of a database with a blockchain. The database, which could be either centralized or decentralized, is designed to handle a large volume of data. In contrast, the blockchain stores only transactions, which may include metadata. This metadata can contain hashes of documents, linking the stored data with its immutable record on the blockchain.

When a document is added to the database, a hash of the document is created and added to the blockchain. The blockchain records the hash along with a timestamp, providing a verifiable, tamper-proof record of the document’s existence and its state at a particular point in time.

When you need to verify the integrity of a document, you retrieve the document from the database, compute its hash, and compare this with the hash stored on the blockchain. If they match, you can be confident that the document has not been tampered with.

This dual system leverages the strengths of both databases and blockchains. The database provides efficient storage and retrieval of large documents, while the blockchain provides a robust, tamper-proof mechanism for ensuring data integrity. It’s a powerful combination for maintaining the integrity of digital documents.

Hashing: The Digital Fingerprint

Hashing is a process that takes an input (like a document) and returns a fixed-size string of bytes. The output, or hash, is akin to a digital fingerprint for the input data. Each unique document will have a unique hash, and even a minor change in the document will produce a completely different hash.

The process of creating a hash from a document involves three steps:

  1. Choose a Hash Function: A hash function is a special type of cryptographic function used in computing. There are many different hash functions to choose from, such as SHA-256 or MD5.
  2. Input the Document: You input your document into the hash function. This document can be of any size and format.
  3. Compute the Hash: The hash function processes the input document and produces a fixed-size string of bytes, typically in the form of a hexadecimal number. This is your hash.

A hash has the following characteristics.

Each unique document will have a unique hash. Even a small change in the document (like adding a period) will produce a completely different hash.

No matter how big or small your document is, the hash will always be the same size.

A hash function is a one-way function. This means that it’s computationally infeasible to reverse the process. Given a hash, you can’t derive the original document.

You can verify the integrity of the document by re-computing the hash and comparing it with the original hash. If they match, the document has not been tampered with.

Storing the Hash on the Blockchain

Once the hash is created, it can be stored on the blockchain. The blockchain is a decentralized and distributed digital ledger that records transactions across multiple computers so that any involved record cannot be altered retroactively, without the alteration of all subsequent blocks.

The real power of hashing comes from its use in verifying the integrity of the document. If you need to verify the document in the future, you can hash the document again and compare this new hash to the one stored on the blockchain. If they match, the document has not been changed. If they don’t match, it means the document has been altered.

The illustration demonstrates the future verification of Document 3. A new hash is generated from Document 3 (taken from the database) and compared with the hash previously stored in Block 3. If the hashes match, it confirms that Document 3 remains unaltered - its content is identical to when Hash 3 was initially recorded in the blockchain.

When the hash of a document is added to the blockchain, it is timestamped.

The timestamp proves that the document existed at a certain point in time. When you store the hash of a document on the blockchain, the network automatically adds a timestamp to it. This timestamp is the exact moment when the hash was added to the blockchain. It serves as proof that the document existed at least as early as the timestamp.

Once a timestamp is added to the blockchain, it can’t be changed. This is because of the blockchain’s immutability property. So, the timestamp serves as an immutable record of when the document’s hash was added to the blockchain.

Timestamps provide a chronological record of when data was added to the blockchain. This traceability is crucial in scenarios where the sequence of events matters, such as in financial transactions or supply chain management.

With timestamps, an entity cannot deny the authenticity of its data. The timestamp serves as proof that the data existed at a certain point in time, preventing entities from denying the origination or receipt of the data.

Traditional databases are typically managed by administrators who have the ability to modify or delete data. This introduces a potential point of vulnerability, as it means that the integrity of the data is dependent on the actions of these administrators. Despite various security measures and protocols, this system cannot inherently guarantee non-repudiation, traceability, verification, and immutability.

Blockchain, on the other hand, operates differently. It is a decentralized system, meaning there is no single administrator with the power to alter or delete data. Instead, all participants in the network maintain and verify the blockchain. This decentralization is what allows blockchain to inherently ensure data integrity.

In a blockchain, data is stored in blocks, and each block is linked to the previous one by including a hash of the previous block. This creates a chain of blocks (hence the name ‘blockchain’) and ensures that all data is traceable and immutable. Once a block is added to the chain, it cannot be changed or removed, which guarantees the immutability of the data.

Furthermore, every transaction on the blockchain is transparent to all participants in the network, which ensures traceability and verification. This transparency, combined with the cryptographic security of the blockchain, ensures non-repudiation.

A Pilot Project For The Dubai Police

The specifics of the system that the Dubai Police is testing with Cardano in their pilot project are not publicly disclosed. However, based on public statements, it’s plausible that the system operates similarly to the one described earlier in this article.

In this system, documents and forensic evidence generated during criminal investigations are stored in a database linked to Cardano, not directly on the blockchain. The Cardano ledger only stores metadata, likely in the form of hashes. These hashes could represent individual documents or entire sets of documents.

The system is expected to employ cryptography and Decentralized Identity (DID) to track who entered information into the system and when.

Additionally, measures must be in place to ensure that only authorized individuals can access the information.

While it’s theoretically possible for documents to be intentionally deleted or lost from the database, an investigator with the original document can demonstrate that the document’s content (he possesses) hasn’t changed since it was entered into the system. This is done by creating a hash of the document and comparing it with the hash recorded in the blockchain, thereby safeguarding the evidence collected during the investigation.


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