standard encryption (AES) [13]. On the other hand, two keys for data encryption are used in
asymmetric encryption: a private key and a public key (public key). RAS (Rivest-Shamir-
Adleman) is an asymmetric crypto algorithm key. In SG, different elements with their own
computing potential coexist. It may be concluded that both the symmetric and the
asymmetric key encryption, and their choice depend on various factors among which are
data criticality, time limitations [14] and computational resources.
Authentication is defined as the action of verifying the validity of the identity of an
object, e.g., using a password. It may be a user, a smart device, or any connected item in the
network of SG. Multicast authentication is a special authenticity type, and its applications
are used extensively in SG. There are three methods of achieving authentication for multi-
emitting applications [15]: secret information asymmetry, time asymmetry and hybrid
asymmetry.
Key management is a critical approach to encryption and authenticity [16]. Managing
public keys or managing shared secrets keys can be used to ensure authenticity for
communication between networks. In the public key infrastructure (PKI), the identities of
the two entities are stored by a certificate issued by a third party, an entity called the
Certification Authority (CA). The mechanism is done prior to establishing connection
between the two entities. In managing a common secret key, four steps are employed to
maintain communication security: key creation, key distribution, key storage, and key
update. Because of the distributed nature of SG, some specific requirements for management
planning should be considered cryptographic key. Basic but important requirements of the
management scheme key are efficiency, growth capacity, scalability, and safe management.
Furthermore, several key management frameworks have been proposed especially for
electricity systems, such as: unique key (single key), installing a key for SCADA systems
(SKE), architecture key management for SCADA systems (SKMA), Advanced Architecture
key management (ASKMA) ASKMA+ and tiered management method cryptographic key
(SMOCK). The selection of a frame is determined by different criteria, including scalability,
computing capacity resources and multipurpose support. Research has been conducted to
compare among the abovementioned key management schemes. It was based on scalability,
multi-emission support, resilience to key violation andapplication to electricity systems.
ASKMA+ and SMOCK presented interesting outcomes. ASKMA+ is an effective key
management scheme supporting multi¬emission, yet it suffers from scalability. SMOCK, on
the other hand, presents good scalability, but it has got some weaknesses amongst which are
nonsupport multi-emission and low computational efficiency.
