Alice and Bob Johnson are a fictional couple often used in computer science and cryptography to illustrate concepts of secure communication. They represent two parties who want to exchange information safely, highlighting the challenges of ensuring privacy and security in their interactions. In various scenarios, Alice and Bob may use different methods, such as encryption or digital signatures, to protect their messages from eavesdroppers. Their names have become synonymous with discussions about public key cryptography and other security protocols, making them important figures in the field of information technology.