Leakagefree

Leakagefree is a term used to describe systems, protocols, or cryptographic primitives that are designed to prevent information about secret inputs from being leaked through observable channels beyond what the protocol’s public outputs reveal. The concept is rooted in information security and cryptography, where leakage can occur via side channels such as timing, power consumption, electromagnetic emissions, or unintended data flows in software and hardware.

In practice, achieving leakagefree operation is challenging. Absolute elimination of all information leakage is often viewed as ideal; real-world designs aim to minimize leakage and bound any residual leakage so that it does not compromise security. Leakagefree designs typically rely on a combination of methods, including constant-time implementations to avoid timing leaks, masking and other probabilistic processing to obscure data-dependent signals, noise injection, and strict hardware isolation. Leakage-resilient cryptography provides a related paradigm that allows for some bounded leakage while maintaining security guarantees, whereas leakagefree ideas aim for no exploitable leakage beyond the intended outputs.

Formal treatment of leakagefree properties may involve models that quantify information leakage and demonstrate that an adversary cannot gain meaningful information about secrets, often through simulation-based or information-theoretic arguments. The term is used as a design principle in secure computing, hardware security modules, smart cards, and other environments where sensitive data processing occurs.

Limitations include the practicality of achieving true leakage-free operation, the evolving nature of side-channel attacks, and the dependence on attacker capabilities. As a concept, leakagefree guides the development of architectures and protocols toward reducing opportunities for information leakage.

See also: leakage-resilient cryptography, side-channel attack, constant-time programming, secure hardware.