This, along with other interview questions on ethical hacking, is a regular feature in ethical hacking interviews, be ready to tackle it with the approach mentioned below. The Blowfish algorithm family is a particular subset of the larger category of cryptography algorithms. These algorithms are employed in low-level cryptographic applications, such as safeguarding the confidentiality and integrity of data while it is being transmitted over an unsecured channel. One example of such an application is protecting data while it is being transferred over an unsecured channel. The Blowfish algorithm makes use of a 64-bit block cypher that runs on 8 rounds of keys that are each created using a different polyalphabetic function with a high probability. The Blowfish algorithm is a substitution cypher, which derives its name from the algorithm. A substitution cypher is a type of encryption in which each letter of the alphabet is changed to a new symbol. This ensures that each letter only appears once in the message.