Attribute-Based Encryption
Attribute-based encryption (ABE), introduced by Sahai and Waters, ties keys and ciphertexts to attribute sets, and decryption succeeds only when the attributes satisfy the access policy.
Purpose
It enables fine-grained access control without encrypting separately for each user, fitting cloud-storage sharing and organizational permission management.
Mechanism
The ciphertext carries an access-policy tree (or attribute set) and the user key carries an attribute set (or policy); decryption requires the ciphertext policy to match the key attributes. In CP-ABE the ciphertext holds the policy and the key holds the attributes; KP-ABE reverses the two.
Use cases
- Fine-grained cloud-storage sharing
- Organizational document permissions
- Broadcast encryption