Trojan Horse
The trojan horse has its origin in the Greek history. During the Trojan war, the Greeks built a giant wooden horse and placed it in front of the gates of troy, the city they tried to enter during the war. They then pretended to give up and the trojan people pulled the horse inside their city as a trophy of their so thought victory. However, inside the trojan horse, there where the best Greek soldiers hidden who then were inside the city and could win the war.
In computing, the term trojan horse is now used for a type of malware, that tricks users by disguising itself as a normal program, so that the user might install it without second thoughts. Trojans are usually used to open a backdoor, so the attacker has unauthorized access to the affected computer. Therefore, the malware is often used for ransomware attacks.