What is backward secrecy?

Backward Secrecy guarantees that a passive adversary who knows a contiguous subset of group keys cannot discover preceding group keys. Key Independence guarantees that a passive adversary who knows any proper subset of group keys cannot discover any other group key. The relationship among the properties is intuitive.

What are attributes in attribute-based encryption?

Attribute-based encryption is a type of public-key encryption in which the secret key of a user and the ciphertext are dependent upon attributes (e.g. the country in which they live, or the kind of subscription they have).

What is forward and backward security?

In cryptography, forward secrecy = perfect forward secrecy, backward secrecy = future secrecy. First, recall some background. The above terms are often discussed in the setting of secure channel establishment protocols, e.g., TLS, Signal, etc.

What is forward secrecy in cryptography?

Perfect forward secrecy means that a piece of an encryption system automatically and frequently changes the keys it uses to encrypt and decrypt information, such that if the latest key is compromised, it exposes only a small portion of the user’s sensitive data.

What is attribute-based signature?

Attribute-based signature (ABS) is a promising cryptographic primitive. It allows the signer to generate a signature with attributes satisfying the predicate without leaking more information, so as to provide message authenticity in an anonymous manner.

How does identity based encryption work?

Identity-based encryption is a type of public-key encryption in which a user can generate a public key from a known unique identifier such as an email address), and a trusted third-party server calculates the corresponding private key from the public key.

How does homomorphic encryption work?

Using a homomorphic encryption scheme, the data owner encrypts their data and sends it to the server. The server performs the relevant computations on the data without ever decrypting it and sends the encrypted results to the data owner. No exponentiating a number by an encrypted one. No non-polynomial operations.