Privacy Enhancing Credential

Full Title or Meme

A collection of private and secret data that can be used to prove an assertion in a manner that does not release more private information than absolutely required for the purpose described. Perhaps that term is used to indicate a mobile computer device, which is the preferred technology solution.

Context

• Regardless of any technology used to protect user data in a credential, it serves no purpose if it is not limited to use in a protected Ecosystem.
• In some contexts, the term "Privacy Enhancing Credential" is used, although there are very few use cases where a credential is not mobile even when it is just a driver's license in a holder's pocket.
• Simple credentials that do not rely on secrets to protect user data are not considered to be of any value as a Privacy Enhancing Credential.
• As a general rule, private data is released only when the user agrees, and secret data is never released. This definition does not apply to private keys, which are seldom released and only in the most secure circumstances, like when a private key is used in several servers that provide the same security service. That would also be the case when the user had more than one mobile Smartphone and desired to have the same functionality on both devices.

Ecosystems

• Perhaps the simplest Ecosystem is a Smart Card which comes with secure private key generation and cannot export the key.
• The Credential could be included and used entirely within the context of a Trusted Execution Environment, or a Secure Enclave and its resident software.

Solutions

Privacy Enhancing Technologies (PETs) are a broad range of technologies designed to protect users’ personal data and enhance their privacy on the internet.

• The Privacy Enhancing Technology Provider is described on a related wiki page.

Selective Disclosure

Selective disclosure credentials are a privacy feature of Digital Credentials that allow individuals to share only the necessary information with organizations, without compromising their privacy. This means that a person can control exactly which pieces of information are disclosed and to whom.

For example, if someone named Ash holds a university degree as a digital credential, it might contain his name, student number, email, and degree name. If he applies for a job and the employer requests to verify his degree, Ash can choose to share only his name and degree name, omitting other details like his student number and email.

The benefits of selective disclosure credentials include:

• Data Minimization: Sharing only the minimum amount of information necessary for a specific transaction or purpose, reducing the risk of data breaches and privacy violations.
• Compliance with Data Regulations: Helps organizations comply with data protection regulations such as the GDPR and CCPA by minimizing the amount of personal data processed and stored.

Verifiable Credentials are like digital versions of traditional paper credentials (e.g., driver's licenses, passports) but with increased security and privacy. They are stored in a secure, tamper-proof format and allow for quick and easy verification. Selective disclosure is a key feature that enhances the privacy and control individuals have over their personal data.

Source: Conversation with Copilot, 8/6/2024

(3) Current Work and Future Trends in Selective Disclosure - self-issued. https://self-issued.info/presentations/EIC_2023_Selective_Disclosure.pdf
(4) undefined. https://www.w3.org/TR/2024/NOTE-vc-overview-20240706/
(5) undefined. https://w3c.github.io/vc-overview/
(6) undefined. https://www.w3.org/standards/history/vc-overview/
(7) undefined. https://www.w3.org/TR/

Zero Knowledge Proof

A zero-knowledge proof is a cryptographic method where one party, the **prover**, can prove to another party, the Verifier, that a certain statement is true, without revealing any information beyond the fact that the statement is indeed true.

Here's a simple analogy to understand the concept: Imagine Peggy has discovered a secret word that opens a magic door in a cave. The cave is shaped like a ring, with the entrance on one side and the magic door on the opposite side. Victor wants to know if Peggy knows the secret word but Peggy doesn't want to reveal her knowledge. To prove she knows the secret word without revealing it, Peggy could enter the cave and emerge from the correct path that the magic door leads to, demonstrating she must know the secret word to pass through it.

In technical terms, zero-knowledge proofs involve a series of interactions where the prover performs actions or provides evidence that convinces the verifier of the truth of a statement, without giving away any additional information. These proofs are particularly useful in situations where privacy is important, such as in blockchain transactions, where they can validate the correctness of a transaction without revealing its details.

Other Technologies

1. Cryptographic algorithms are mathematical algorithms that ensure the confidentiality, integrity, and authenticity of data¹.
2. Homomorphic Encryption is an encryption method allows computations to be performed on encrypted data without decrypting it².
3. AI-generated Synthetic Data involves creating artificial data that can be used in place of real data to protect individuals' privacy³.
4. Secure Multi-party Computation allows parties to jointly compute a function over their inputs while keeping those inputs private³.
5. Federated Learning is a machine learning approach where the model is trained across multiple decentralized devices holding local data samples, without exchanging them³.
6. Differential Privacy is a system for publicly sharing information about a dataset by describing the patterns of groups within the dataset while withholding information about individuals in the dataset⁴.
7. Anonymizing Networks help users to hide their physical location and usage from anyone conducting network surveillance or traffic analysis⁵.
8. Anti-tracking Tools are used to prevent online services from tracking users' browsing activities⁵.
9. Virtual Private Networks (VPNs) create a secure and encrypted connection over a less secure network, such as the internet⁵.
10. Secure Messaging refers to the encryption of messages to protect the content from being read by unintended recipients⁵.
11. See the wiki page on Blockchain Privacy which can be described as privacy preserving even though the entire chain is publicly accessible.

Source: Conversation with Copilot, 8/6/2024

(1) Privacy-enhancing technologies - Wikipedia. https://en.wikipedia.org/wiki/Privacy-enhancing_technologies.
(2) Explore Top 10 Privacy Enhancing Technologies & 3 Benefits. https://research.aimultiple.com/privacy-enhancing-technologies/.
(3) What are privacy enhancing technologies? The 5 best PETs for the modern .... https://mostly.ai/blog/what-are-privacy-enhancing-technologies.
(4) Privacy Enhancing Technologies: An Introduction for Technologists. https://martinfowler.com/articles/intro-pet.html.
(5) Privacy Enhancing Technologies – A Review of Tools and Techniques .... https://www.priv.gc.ca/en/opc-actions-and-decisions/research/explore-privacy-research/2017/pet_201711/.

References

Other Material

• Also see wiki page on Privacy Harms.