identity_credential 1.5.1

An implementation of the Verifiable Credentials standard.
Documentation 
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// Copyright 2020-2024 IOTA Stiftung, Fondazione Links
// SPDX-License-Identifier: Apache-2.0

use crate::error::Error;
use crate::error::Result;
use jsonprooftoken::jwp::header::PresentationProtectedHeader;
use jsonprooftoken::jwp::issued::JwpIssued;
use jsonprooftoken::jwp::presented::JwpPresentedBuilder;

/// Used to construct a JwpPresentedBuilder and handle the selective disclosure of attributes.
// - @context MUST NOT be blinded
// - id MUST be blinded
// - type MUST NOT be blinded
// - issuer MUST NOT be blinded
// - issuanceDate MUST be blinded (if Timeframe Revocation mechanism is used)
// - expirationDate MUST be blinded (if Timeframe Revocation mechanism is used)
// - credentialSubject (Users have to choose which attribute must be blinded)
// - credentialSchema MUST NOT be blinded
// - credentialStatus MUST NOT be blinded
// - refreshService MUST NOT be blinded (probably will be used for Timeslot Revocation mechanism)
// - termsOfUse NO reason to use it in ZK VC (will be in any case blinded)
// - evidence (Users have to choose which attribute must be blinded)
pub struct SelectiveDisclosurePresentation {
  jwp_builder: JwpPresentedBuilder,
}

impl SelectiveDisclosurePresentation {
  /// Initialize a presentation starting from an Issued JWP.
  /// The following properties are concealed by default:
  ///
  ///   - `exp`
  ///   - `expirationDate`
  ///   - `issuanceDate`
  ///   - `jti`
  ///   - `nbf`
  ///   - `sub`
  ///   - `termsOfUse`
  ///   - `vc.credentialStatus.revocationBitmapIndex`
  ///   - `vc.credentialSubject.id`
  pub fn new(issued_jwp: &JwpIssued) -> Self {
    let mut jwp_builder = JwpPresentedBuilder::new(issued_jwp);

    jwp_builder.set_undisclosed("jti").ok(); // contains the credential's id, provides linkability

    jwp_builder.set_undisclosed("issuanceDate").ok(); // Depending on the revocation method used it will be necessary or not
    jwp_builder.set_undisclosed("nbf").ok();

    jwp_builder.set_undisclosed("expirationDate").ok(); // Depending on the revocation method used it will be necessary or not
    jwp_builder.set_undisclosed("exp").ok();

    jwp_builder.set_undisclosed("termsOfUse").ok(); // Provides linkability so, there is NO reason to use it in ZK VC

    jwp_builder
      .set_undisclosed("vc.credentialStatus.revocationBitmapIndex")
      .ok();

    jwp_builder.set_undisclosed("vc.credentialSubject.id").ok();
    jwp_builder.set_undisclosed("sub").ok();

    Self { jwp_builder }
  }

  /// Selectively conceal "credentialSubject" attributes.
  /// # Example
  /// ```ignore
  /// {
  ///     "id": 1234,
  ///     "name": "Alice",
  ///     "mainCourses": ["Object-oriented Programming", "Mathematics"],
  ///     "degree": {
  ///         "type": "BachelorDegree",
  ///         "name": "Bachelor of Science and Arts",
  ///     },
  ///     "GPA": "4.0",
  /// }
  /// ```
  /// If you want to undisclose for example the Mathematics course and the name of the degree:
  /// ```ignore
  /// presentation_builder.conceal_in_subject("mainCourses[1]");
  /// presentation_builder.conceal_in_subject("degree.name");
  /// ```
  pub fn conceal_in_subject(&mut self, path: &str) -> Result<(), Error> {
    let _ = self
      .jwp_builder
      .set_undisclosed(&("vc.credentialSubject.".to_owned() + path))
      .map_err(|_| Error::SelectiveDisclosureError);
    Ok(())
  }

  /// Undisclose "evidence" attributes.
  /// # Example
  /// ```ignore
  /// {
  ///   "id": "https://example.edu/evidence/f2aeec97-fc0d-42bf-8ca7-0548192d4231",
  ///   "type": ["DocumentVerification"],
  ///   "verifier": "https://example.edu/issuers/14",
  ///   "evidenceDocument": "DriversLicense",
  ///   "subjectPresence": "Physical",
  ///   "documentPresence": "Physical",
  ///   "licenseNumber": "123AB4567"
  /// }
  /// ```
  /// To conceal the `licenseNumber` field:
  /// ```ignore
  /// presentation_builder.conceal_in_evidence("licenseNumber");
  /// ```
  pub fn conceal_in_evidence(&mut self, path: &str) -> Result<(), Error> {
    let _ = self
      .jwp_builder
      .set_undisclosed(&("vc.evidence.".to_owned() + path))
      .map_err(|_| Error::SelectiveDisclosureError);
    Ok(())
  }

  /// Set Presentation Protected Header.
  pub fn set_presentation_header(&mut self, ph: PresentationProtectedHeader) {
    self.jwp_builder.set_presentation_protected_header(ph);
  }

  /// Get the builder.
  pub fn builder(&self) -> &JwpPresentedBuilder {
    &self.jwp_builder
  }
}