Research Article
Analysis and Evaluation of Schemes for Secure Sum in Collaborative Frequent Itemset Mining across Horizontally Partitioned Data
Algorithm 2
Proposed algorithm for secure sum in PPDFIM using symmetric keys.
Setup: Each party exchanges its seed with the STTP securely. | ( is the plain text at the th party) (); ; .
| Frequentitems = . | Require: . | (1) for each global candidate itemset = 1 to | (2) for each party ( | Encryption phase: | (3) Each party has a secret where is the modulus | (4) Each party generates a key stream where is the modulus | (5) Ciphertext mod | (6) end for | Aggregation: | (7) cipherSum = 0 | (8) for = 1 to | (9) cipherSum = cipherSum + mod | (10) sends cipherSum to | (11) end for | Decryption at STTP: | (12) Sum = cipherSum | (13) Sum = Sum − mod | (14) broadcasts the value of Sum to all the parties | (15) if (Sum > global support threshold) | (16) Frequentitems = Frequentitems Itemset | (17) end for | (The same procedure is followed for finding the frequent association rules | once the frequent itemsets are deciphered in case of PPDARM.) | * sends the sum value to which is a semi-honest trusted third party (STTP). | (i) If Sum = > , decryption produces Sum < . In practice, must be chosen as . |
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