Unicode is a text encoding standard that assigns code points to characters from many writing systems, plus special-use and non-printing characters. It lets computers represent the same text consistently across languages, but it also includes characters that can be invisible on screen or behave differently from ordinary letters.
In cyber security, Unicode matters because attackers can abuse those hidden code points to confuse filters, logging, and keyword detection. A phishing lure may look normal to a person while the underlying string is split by non-printing characters, making simple exact-match rules fail. Defenders reduce this risk by normalizing text before scoring, preserving the raw message for analysis, and treating unusual code points as a signal for further review. Unicode is not inherently dangerous, but inconsistent handling of it can create blind spots in email security, web filters, and detection pipelines.