Feature Friday n°13: Data Functions
Introduction
Hey friends,
Welcome to Feature Friday! This series highlights new digital identity features and concepts that can be used via the walt.id stack. For feedback or episode suggestions, connect with us on Discord!
Today, we learn how we can make sure that our issued credentials always contain up-to-date and most current information by using the data functions offered by the walt.id issuer API.
What Data Functions Are
Data functions are a unique feature provided by the walt.id issuer API intended to maintain the authenticity and relevance of the Verifiable Credentials (VCs) issued. Distinct from typical functions, data functions are triggered not at the time of invoking the issuer API to construct the OpenID for Verifiable Credential (OID4VC) offer URL. Instead, their execution is deferred until the moment the VC is claimed by the recipient.
This design approach provides several key advantages:
Time-Relevant Execution: This delayed execution captures any changes that might have occurred post-credential offer creation but pre-claim, assuring that the issued credential is in its most current and accurate state when claimed.
Unknown Attribute Assignment: Data functions allow the assignment of attribute values in the credential to values that are unknown at the time of crafting the credential issuance offer, like the subject's DID. This allows for flexibility and accuracy in situations where certain values cannot be determined at the time of credential issuance, but will become known once the recipient claims the credential.
What Types Of Data Functions We Offer
Below is a sample subset of our data functions. For a complete list, please refer to our documentation.
UUID: Generates a unique identifier.
Timestamp: Provides the current timestamp in ISO 8601 format.
Webhook: Makes a request to a specific URL and inserts the response as a string.
Demo
A short demo showcasing how you can use the data policies of the walt.id issuer API.
Get Started
Now, here's your dose of tech humour for the day:
Why did the programmer go broke?
Because he used up all his cache.
Catch you next Friday! Until then, feel free to join us on discord!
Best,
Tamino from walt.id