A verifiable credential (VC) is a digital file that contains one or more key-value claims (e.g., birth date, name, qualifications, gender, citizenship, skills, etc.) about an entity (the subject), issued by another entity (the issuer), and is verifiable by any entity (the verifier).
Each type of Verifiable Credential (VC) follows the basic scheme proposed by the W3C that defines the fields and data types. Similarly, it is possible to extend the proposed standard through schemes that define the new fields within a specific type of credential.
The schema of a VC is typically a JSON-LD file that describes the fields that the credential can contain, and the credential must point to that file through the “@context” field. Therefore, the JSON-LD file associated with the credential schema must exist in a public place where it can be accessed for later validation.
Within the identity stack and with the purpose of maintaining a control of credential types, LACChain has created a LACChain Credential Repository where any entity can register its type of credential along with the associated schema for later publication within the registry that is located at https://id.lacchain.net.
LACChain has built and maintains a public library of VCs that is aimed to incorporate VCs designed for and used in real use cases across Latin America and the Caribbean in areas such as education, health, energy, public administration services, and land registry, among others. This library can be found in this domain.
The LACChain Framework presents a process to verify verifiable credentials consisting on the following steps:
Currently, there are not many solutions for the exchange of credentials (i.e., for issuers to send them to subjects and for subjects to present them to verifiers when it is not through a QR code), some proposals consist of exchange protocols over the internet (see DIDComm). LACChain has developed an ad-hoc solution for the exchange of Verifiable Credentials, exposing a REST API as an SMTP mail service. The LACChain Mailbox is a secure and private system for the exchange of messages, VCs, and VPs. It is a controlled by a centralized service that allows entities identified using DIDs to send and receive messages that are stored encrypted in a secure database.