Types of Persistent Identifiers

Oct 13, 2025 by wbrum.org 24 views

Introduction

In the digital age, persistent identifiers have become an essential component of digital preservation and citation. The Persistent URL (PURL) 1 definition, however, lacks clarity on the specific persistent identifiers being checked. In this article, we will delve into the world of persistent identifiers, exploring their definitions, types, and significance in digital preservation.

What are Persistent Identifiers?

Persistent identifiers are unique strings of characters that serve as a permanent reference to a digital object, such as a document, image, or dataset. They are designed to remain unchanged over time, even if the underlying digital object is modified or relocated. Persistent identifiers enable users to access and cite digital resources with confidence, ensuring that the information remains accessible and reliable.

Types of Persistent Identifiers

Several types of persistent identifiers are widely used in digital preservation and citation. These include:

1. W3ID (Web3 Identifier)

A W3ID is a type of persistent identifier that uses the Web3 protocol to create a unique identifier for a digital object. W3IDs are generated using a cryptographic hash function, which ensures that the identifier remains unchanged even if the underlying digital object is modified. W3IDs are often used in decentralized applications and blockchain-based systems.

2. PURL (Persistent URL)

A PURL is a type of persistent identifier that uses a URL to reference a digital object. PURLs are designed to remain unchanged over time, even if the underlying digital object is relocated or modified. PURLs are often used in digital libraries and archives to provide a stable reference to digital resources.

3. DOI (Digital Object Identifier)

A DOI is a type of persistent identifier that is assigned to a digital object by a registration agency. DOIs are designed to remain unchanged over time, even if the underlying digital object is modified or relocated. DOIs are widely used in academic publishing and research to provide a stable reference to digital resources.

4. W3C URL (World Wide Web Consortium URL)

A W3C URL is a type of persistent identifier that is used to reference a digital object on the World Wide Web. W3C URLs are designed to remain unchanged over time, even if the underlying digital object is modified or relocated. W3C URLs are often used in web development and digital preservation to provide a stable reference to digital resources.

What is Being Measured?

The PURL 1 definition lacks clarity on the specific persistent identifiers being checked. However, based on the types of persistent identifiers discussed above, it is clear that the following persistent URLs are being measured:

W3ID
PURL
DOI
W3C URL

These persistent identifiers are essential components of digital preservation and citation, and their presence ensures that digital resources remain accessible and reliable over time.

Conclusion

In conclusion, the PURL 1 definition requires clarification on the specific persistent identifiers being checked. The types of persistent identifiers discussed above, including W3ID, PURL, DOI, and W3C URL, are essential components of digital preservation and citation. By understanding these persistent identifiers, users can ensure that digital resources remain accessible and reliable over time.

Recommendations

Based on the discussion above, we recommend the following:

Clarify the PURL 1 definition to specify the types of persistent identifiers being checked.
Provide a detailed definition of each type of persistent identifier, including W3ID, PURL, DOI, and W3C URL.
Emphasize the importance of persistent identifiers in digital preservation and citation.

Introduction

In our previous article, we explored the world of persistent identifiers, discussing their definitions, types, and significance in digital preservation. In this article, we will delve into a Q&A guide, addressing common questions and concerns related to persistent URLs.

Q&A Guide

Q: What is a persistent identifier?

A: A persistent identifier is a unique string of characters that serves as a permanent reference to a digital object, such as a document, image, or dataset. They are designed to remain unchanged over time, even if the underlying digital object is modified or relocated.

Q: What types of persistent identifiers are there?

A: There are several types of persistent identifiers, including:

W3ID (Web3 Identifier)
PURL (Persistent URL)
DOI (Digital Object Identifier)
W3C URL (World Wide Web Consortium URL)

Q: What is a W3ID?

A: A W3ID is a type of persistent identifier that uses the Web3 protocol to create a unique identifier for a digital object. W3IDs are generated using a cryptographic hash function, which ensures that the identifier remains unchanged even if the underlying digital object is modified.

Q: What is a PURL?

A: A PURL is a type of persistent identifier that uses a URL to reference a digital object. PURLs are designed to remain unchanged over time, even if the underlying digital object is relocated or modified.

Q: What is a DOI?

A: A DOI is a type of persistent identifier that is assigned to a digital object by a registration agency. DOIs are designed to remain unchanged over time, even if the underlying digital object is modified or relocated.

Q: What is a W3C URL?

A: A W3C URL is a type of persistent identifier that is used to reference a digital object on the World Wide Web. W3C URLs are designed to remain unchanged over time, even if the underlying digital object is modified or relocated.

Q: Why are persistent identifiers important?

A: Persistent identifiers are essential components of digital preservation and citation. They ensure that digital resources remain accessible and reliable over time, even if the underlying digital object is modified or relocated.

Q: How do I create a persistent identifier?

A: The process of creating a persistent identifier varies depending on the type of identifier. For example, W3IDs are generated using a cryptographic hash function, while PURLs are created using a URL. DOIs are assigned by a registration agency, and W3C URLs are created using a URL.

Q: Can I use a persistent identifier to reference a digital object that no longer exists?

A: No, persistent identifiers are designed to reference digital objects that exist at the time of creation. If a digital object is deleted or no longer exists, the persistent identifier will no longer be valid.

Q: Can I use a persistent identifier to reference a digital object that has been modified?

A: Yes, persistent identifiers are designed to remain unchanged even if the underlying digital object is modified. However, it is essential to ensure that the persistent identifier is updated to reflect any changes to the digital object.

Q: How do I resolve a persistent identifier?

A: Resolving a persistent identifier involves accessing the digital object referenced by the identifier. This can be done using a URL or other methods, depending on the type of identifier.

Q: Can I use a persistent identifier to reference a digital object that is not publicly accessible?

A: Yes, persistent identifiers can be used to reference digital objects that are not publicly accessible. However, it is essential to ensure that the persistent identifier is not publicly accessible, and that access is restricted to authorized individuals or groups.

Conclusion

In conclusion, persistent identifiers are essential components of digital preservation and citation. By understanding the types of persistent identifiers, their importance, and how to create and resolve them, users can ensure that digital resources remain accessible and reliable over time.

Recommendations

Based on the discussion above, we recommend the following:

Use persistent identifiers to reference digital objects in digital preservation and citation.
Ensure that persistent identifiers are created and resolved correctly to avoid errors.
Use a persistent identifier to reference a digital object that is not publicly accessible, and restrict access to authorized individuals or groups.
Update persistent identifiers to reflect any changes to the digital object.

By following these recommendations, users can ensure that digital resources remain accessible and reliable over time, and that the persistent identifiers are used correctly.