Patent ID: 11868510
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 1:
2. The secure cross tabulation system according to claim 1, wherein
F is an arbitrary ring; nk is an integer greater than or equal to 1; and [k0], [knk−1] are shares obtained by secret sharing of key attributes k0, knk−1∈Fm, and
the processing circuitry is further configured to:
generate, from a share {b} that becomes a bit string b:=b0, . . . , bm−1 obtained by bit decomposition and concatenation of the key attributes k0, . . . , knk−1 when reconstructed, a share {{σ0}} that becomes permutation σ0 for performing a stable sort of the bit string b in ascending order when reconstructed, using the shares [k0], . . . , [knk−1],
generate a share {b′} that becomes a sorted bit string b′:=b′0, . . . , b′m−1 which is the bit string b as sorted by the permutation σ0 when reconstructed, using the share {b} and the share {{σ0}},
generate the share {e} that becomes the flag e:=e0, . . . , em−1 when reconstructed, using the share {b′}, by setting {ei}:={b′i≠b′i+1} for each integer i greater than or equal to 0 and smaller than or equal to m−2 and setting {em−1}:={1}, and
generate the share {{σ}} that becomes the permutation a for performing a stable sort of negation ¬e of the flag e in ascending order when reconstructed, using the share {e}.