The field of digital identity is not without its complexities. In this second installment of our two-part series on digital identity terminology, we’ll continue to explore the critical components that define digital identity: Credential Service Providers (CSPs), Identity Providers (IdPs), and Verifiers.
In the first blog, we explored the fundamental differences between CSPs and IdPs. Now, we’ll take that understanding to a more granular level by examining the nature of credentials issued by these entities.
Contrasting CSP and IdP Credentials
Credential Service Providers (CSPs) issue what some might call “self-contained” credentials. These credentials encompass a wealth of information, including user attributes, expiration details, digital signatures for authenticity verification, and often a built-in authenticator, typically employing asymmetric cryptography.
In contrast, Identity Providers (IdPs) take a distinctive approach. Instead of bundling all this information into a single object, IdPs divide it into four distinct parts. With the Verifier functionality integrated into the IdP, users enjoy flexibility in selecting authenticators. Let’s delve into four contents of these credentials:
- User Attributes: IdPs verify and maintain user attributes. However, this information resides in a database managed by the IdP rather than a digitally signed object provided to the user. When asserting information about an authenticated user, the IdP generates a digitally signed ederation assertion containing requested user attributes.
- Expiration and Revocation: IdPs seamlessly handle credential expiration and revocation as part of their functionality. If a user’s account is revoked or has expired, the IdP simply fails to send a federation assertion to the application.
- Digital Signatures: Federation assertions generated by IdPs come with digital signatures that vouch for their authenticity and trustworthiness. These signatures also protect the attributes of the authenticated user.
- Authentication: Unlike self-contained credentials with built-in authenticators, IdP users authenticate directly with the IdP’s Verifier functionality. This grants users the advantage of a broader range of authenticators. Application developers readily support the federation protocols employed by IdPs, enhancing adoption.
Pros and Cons of CSPs and IdPs
In the expansive realm of digital identity, CSPs and IdPs serve distinct purposes, each with its own set of advantages and disadvantages. Let’s explore the pros and cons of both CSPs and IdPs to shed light on their roles in the digital identity landscape.
- Versatile Credential Usage. CSPs issue credentials that are not limited to specific applications. These credentials can be used anywhere the user desires, offering a broad scope of application.
- Strong Authentication. Many CSPs employ asymmetric cryptography for authentication, recognized as one of the most secure methods for online authentication. If you’re interested to learn more, the first half of this video uses a very intuitive approach to describe how asymmetric cryptography works in simple terms.
- Holistic Approach. CSP credentials often extend beyond authentication, enabling functionalities like digital signatures and encryption, making them comprehensive tools for digital identity.
- User-Experience Challenges. Traditional CSP credentials are often perceived as complex to the average user. While new types of CSPs are emerging, such as Verifiable Credentials, they have not yet gained mainstream familiarity.
- Limited Verifier Support. Verifiers, the entities responsible for authentication, do not widely support CSP-type credentials. This creates a disconnect between the capabilities of CSPs and their utilization by everyday consumers.
- Credential Management Complexity. Updating CSP-issued credentials can be cumbersome, involving multiple steps and potentially increasing the user’s burden. Emerging standards aim to simplify this process but are not widely adopted or tested.
- Convenient Authentication Methods. IdPs offer a wide array of familiar and convenient authentication methods for users, enhancing the user experience.
- Developer-Friendly Federation Protocols. Federation protocols supported by IdPs are well-understood by application developers, promoting their adoption across various sectors.
- Privacy Concerns. IdPs, by virtue of users signing in with them, have visibility into all the applications accessed by users. This visibility can raise privacy concerns, necessitating technical or policy-based solutions.
- Limited Functionality. IdP credentials primarily serve authentication purposes and do not support digital signatures or peer-to-peer encryption.
- Configuration and Scaling Challenges. IdPs require manual configuration with each application, limiting their scalability. Furthermore, the business models of IdPs often involve charging applications for integration, further restricting user access.
CSPs and IdPs each contribute significantly to the digital identity landscape, with their own strengths and weaknesses. However, it’s important to note that one is not inherently superior to the other in all contexts. As digital identity technology continues to evolve, innovations and adaptations in both CSP and IdP domains aim to provide users with more seamless and secure digital identity solutions.
DirectTrust has supported CSPs for many years for use in Direct Secure Messaging and other purposes. Given the recent popularity in IdP technology for healthcare users, DirectTrust has begun building programs to accredit IdPs to ensure they meet healthcare industry needs and operate a service that patients can trust. We are actively helping pioneer the advancement of new technology standards by partnering with UDAP.org, aimed at expanding IdP technologies. This collaboration seeks to enhance the accessibility of consumers’ health data in a way that is secure and trustworthy for all.
Kyle Neuman is DirectTrust’s Director of Trust Framework Development.