Module abe 

Attribute-Based Encryption (ABE) for fine-grained access control.

This module provides Ciphertext-Policy ABE (CP-ABE), where access policies are embedded in ciphertexts and user keys are associated with attributes.

Overview

ABE enables encryption to a set of attributes rather than to specific public keys. Only users whose attributes satisfy the access policy can decrypt.

Architecture

• Authority: Generates master keys and issues user keys based on attributes
• Encryptor: Encrypts data with an access policy (e.g., “admin AND (vip OR premium)”)
• Decryptor: Can decrypt if their attributes satisfy the policy

Use Cases in CHIE

• Content access control based on subscription tiers
• Geographic restrictions (region attributes)
• Time-based access (time-period attributes)
• Role-based access (role attributes)

Example

use chie_crypto::abe::{AbeAuthority, AccessPolicy, PolicyNode};

// Authority generates master keys
let mut authority = AbeAuthority::new();

// Issue user key with attributes
let user_attrs = vec!["premium".to_string(), "us-region".to_string()];
let user_key = authority.generate_user_key(&user_attrs)?;

// Encrypt with policy: premium AND us-region
let policy = AccessPolicy::and(vec![
    PolicyNode::Attribute("premium".to_string()),
    PolicyNode::Attribute("us-region".to_string()),
]);
let plaintext = b"Premium US content";
let ciphertext = authority.encrypt(&policy, plaintext)?;

// User can decrypt because they have both attributes
let decrypted = authority.decrypt(&user_key, &ciphertext)?;
assert_eq!(decrypted, plaintext);

Structs

AbeAuthority

ABE authority that manages keys and performs encryption/decryption.

AbeCiphertext

Attribute-based ciphertext.

AccessPolicy

Access policy for CP-ABE encryption.

MasterSecretKey

Master secret key for ABE authority.

UserSecretKey

User secret key containing keys for specific attributes.

Enums

AbeError

Errors that can occur in ABE operations.

PolicyNode

A node in an access policy tree.

Type Aliases

AbeResult

Result type for ABE operations.