Description: An untrusted environment refers to a context where the security and integrity of information cannot be guaranteed. This can include public networks, open systems, or any situation where data can be intercepted or manipulated by malicious actors. In cryptography, this concept is fundamental, as encryption and authentication methods are specifically designed to protect information in these environments. The main characteristics of an untrusted environment include the possibility of man-in-the-middle attacks, lack of control over connected devices, and exposure to malware. The relevance of understanding these environments lies in the increasing reliance on technology in everyday life, where communication and data exchange often occur on platforms that do not offer security guarantees. Therefore, cryptography becomes an essential tool for safeguarding privacy and data integrity in these contexts, allowing users and organizations to operate with a level of trust despite the inherent vulnerabilities of the environment.