Transmission is the act of sending data from one place to another through a communication channel, such as a cable, radio link, or network connection. In cyber security, transmission matters because data is often most exposed while it is moving. If a message is sent in clear text, attackers may intercept, read, modify, or replay it. That is why secure systems use encryption, authentication, and integrity checks during transfer.
Transmission appears in many real-world security scenarios. Phishing kits rely on transmitted payloads and stolen credentials crossing systems; malware may exfiltrate data over web requests, DNS, or wireless links; and defenders inspect traffic for unusual destinations, protocols, or volumes. Even simple demonstrations that move information from one medium to another, such as storing data on paper and then sending it over radio, highlight a basic security lesson: the safety of data depends not only on where it is stored, but also on how it is transmitted.