Unsigned code is software, scripts, or binaries that do not carry a trusted digital signature. On systems with integrity controls, signature checks help prove where code came from and whether it has been altered. If the signature is missing, invalid, or untrusted, the platform may refuse to load it or may treat it with lower trust.
In cyber security, unsigned code matters because it is often a signal of risk. Defenders use signature enforcement, application control, and reputation checks to block unverified payloads, especially in sensitive areas like protected services or endpoint security tools. Attackers, by contrast, may try to route execution through a trusted component so that unsigned code can run indirectly, even when direct loading would be blocked. Monitoring for unsigned modules, unexpected DLL loads, and integrity-policy bypasses helps expose that abuse.