| blackBoxRanksDS {dsBase} | R Documentation |
The second key serverside function that prepares the global ranks of the the real data only generated in the first stage of the ranking procedure and encrypts them in preparation for generating global ranks that correspond 1 to 1 with only the real data in V2BR.
blackBoxRanksDS(input.var.name = NULL, shared.seedval)
input.var.name |
a character string specifying the name of the vector holding the global ranks. This argument is set automatically by the clientside function ds.ranksSecure |
shared.seedval |
a pseudorandom number seed that ensures that the processes generating the order and parameterisation of the encryption algorithms are the same in each study. This argument is set by the argument <shared.seed.value> in the clientside function ds.ranksSecure. The seed value shared by all studies in setting up the encryption procedures in blackBoxRanksDS is arbitrarily changed from that used to set up the encryption procedures in blackBoxDS, so the the set of 7 encryption algorithms is deliberately different. For more details, including future plans to share this starting seed in a more secure way, please see the associated document entitled "secure.global.ranking.docx" and the header file for ds.ranksSecure. |
Severside assign function called by ds.ranksSecure. It takes the global ranks currently held in sR5.df which reflect the global ranks based on the "combined real+pseudo data vector" as encrypted by blackBoxDS but with all pseudo-data stripped out. It then uses these global ranks (of the real data) as if they were a new variable to be ranked. This is then equivalent to blackBoxDS with the primary difference that no pseudo-data are needed. This is because the global ranks are fundamentally non-disclosive and so can be transferred to the clientside with no risk of disclosure. However, in order to ensure that the client cannot compare the list of global.ranks in sR4.df (after initial global ranking based on ranking of real and pseudo-data combined) with the global.ranks to be generated by blackBoxRanksDS (based solely on the real data they are processed through seven more rounds of encryption as before in blackBoxDS. In consequence the client remains unable to determine which of the original global ranks corresponded to real data and which to pseudo-data. In addition, blackBoxRanksDS does not need to determine the number of decimal places in the data because it is only applied to ranks which are assumed to be integers. For more details about the cluster of functions that collectively enable secure global ranking and estimation of global quantiles see the associated document entitled "secure.global.ranking.docx". Also see the header file for ds.ranksSecure and the header file for blackBoxDS
writes a data frame object entitled blackbox.ranks.df to the serverside. In each study this contains the encrypted global ranks and a range of other key components from the second stage (ranking of global ranks for real observations only) of the ranking procedure. For more details see the associated document entitled "secure.global.ranking.docx"
Paul Burton 9th November, 2021