Ransomware is a type of malware (computer virus) which encrypts data, and asks for a ransom in return for the decryption of that data.
MITM: Man-in-the-Middle
MITM is an acronym for Man-in-the-Middle, this is a type of cyber attack where an attacker intercepts or eavesdrops authentic communication. This particular attack is made simpler on unencrypted and poorly encrypted communications.
IDS: Intrusion Detection System
IoT: Internet of Things
The Internet of Things (IoT) is a general term for the/a distributed network of devices typically used for the sensing and analysis of the physical world. IoT devices include smart home appliances such as personal assistants (including Amazon Echo and Google Home), “smart light bulbs,” “smart thermostats” and “smart meters.”
A subset of IoT is Industrial IoT, or IIoT, which is IoT for industrial sectors.
DoS: Denial of Service
A DoS is Denial of Service which is a kind of cyber attack. See also DDoS.
DDoS: Distributed Denial of Service
DDoS is an acronym for Distributed Denial of Service, which is a type of cyber attack which aims to bring down a system or device.
Cipher / Cypher
A cipher (or cypher) is an algorithm that is used for the encryption/decryption of data.
CERT: Computer Emergency Response Team
CERT is an acronym for Computer Emergency Response Team. There are geographical CERTs, such as CERTs for a local or national areas. There are also subject specific CERTs, such as CERTs for ICS.