Module anonymous_credentials 

Anonymous Credentials (Idemix-style) for privacy-preserving authentication

This module implements a simplified anonymous credential system inspired by IBM’s Idemix (Identity Mixer). It provides:

• Credential issuance without revealing user identity
• Selective disclosure of attributes
• Unlinkable presentations (same credential, different presentations are unlinkable)
• Revocation support

Example

use chie_crypto::anonymous_credentials::*;

// Setup issuer
let issuer = Issuer::new();

// User creates credential request
let user = User::new();
let request = user.create_credential_request(&issuer.public_key()).unwrap();

// Issuer issues credential with attributes
let mut attributes = std::collections::HashMap::new();
attributes.insert("age".to_string(), vec![18]); // Age >= 18
attributes.insert("country".to_string(), vec![1]); // Country code 1

let credential = issuer.issue_credential(&request, &attributes).unwrap();

// User creates presentation revealing only age >= 18
let mut revealed = std::collections::HashSet::new();
revealed.insert("age".to_string());

let presentation = user.create_presentation(&credential, &revealed).unwrap();

// Verifier checks presentation
assert!(issuer.verify_presentation(&presentation, &revealed).unwrap());

Structs

AnonymousCredential

Anonymous credential

CredentialPresentation

Credential presentation (proof of possession without revealing credential)

CredentialRequest

Credential request from user

Issuer

Issuer of anonymous credentials

IssuerPublicKey

Issuer public key

User

User holding anonymous credentials

Enums

AnonCredError

Anonymous credentials error types

Type Aliases

AnonCredResult

Result type for anonymous credentials operations