Illustration of the three entities involved in genotype imputation using proxy panel–based outsourcing. Query and reference panels are owners (or controllers) of the respective panels. Imputation server is designated as the processor of the panels. Each step of the protocol is denoted with the corresponding index: (1) The query site initiates the protocol by sending the typed variant loci to the reference site; (2) the reference site generates and sends proxy mechanism parameters; (3a,b) the reference and query sites generate proxy panels and upload to the imputation server; and (4) the imputation server sends the imputed results to the query site.
