An intermediate representation, or IR, is a compiler’s working format between source code and machine code. Instead of translating a program directly from a high-level language to a target CPU, the compiler lowers it into a form that is easier to analyze, optimize, and transform. In projects like homomorphic encryption compilers, the IR may model encrypted arithmetic, control flow, and resource limits more explicitly than the original code.
In cyber security, IR matters because it becomes part of the trust boundary. Secure systems depend on the compiler to preserve correctness while enforcing constraints such as constant-time behavior, encryption parameters, or safe memory use. Bugs or weak assumptions in IR passes can create functional failures, side channels, or dangerous miscompilations. Defenders use IR for static analysis, hardening, and verification, while attackers may target compiler pipelines to exploit parsing gaps, logic errors, or backend-specific weaknesses.