Cryptographic hashing using chaotic hydrodynamics

Significance An essential component of digital communication is hashing, in which a complex piece of information (a document, video, etc.) is mathematically transformed into a unique signature that can later be used to identify the original piece of data. Here, we show that this process bears strong similarity to the chaotic behavior of certain types of flows observed when ordinary fluids mix, such as the stirring of dye into water. We use this analogy between rearranging information and stirring a fluid to construct a fluid-based hash function with comparable properties to traditional algorithms. Our work bears direct relevance to cases in which the physical representation of information affects its transmission, including in microfluidic self-assembly schemes and characterizing complex natural flows.