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Other interesting issues:

Other interesting issues:. Compression within record - e.g. code selection collection of records - e.g. find common patterns Encryption. Encrypting Records. new record r. E(r). trusted processor. dbms. E(r 1 ) E(r 2 ) E(r 3 ) E(r 4 ). Encrypting Records. search F(r)=x. ??.

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Other interesting issues:

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  1. Other interesting issues: • Compression • within record - e.g. code selection • collection of records - e.g. find common patterns • Encryption Notes 3

  2. Encrypting Records new record r E(r) trusted processor dbms E(r1) E(r2) E(r3) E(r4) ... Notes 3

  3. Encrypting Records search F(r)=x ?? trusted processor dbms E(r1) E(r2) E(r3) E(r4) ... Notes 3

  4. Search Key in the Clear search k=2 Q: k=2 A: [2, E(b2)] trusted processor dbms [1, E(b1)] [2, E(b2)] [3, E(b3)] [4, E(b4)] ... • each record is [k,b] • store [k, E(b)] • can search for records with k=x Notes 3

  5. Encrypt Key search k=2 Q: k’=E(2) A: [E(2), E(b2)] trusted processor dbms [E(1), E(b1)] [E(2), E(b2)] [E(3), E(b3)] [E(4), E(b4)] ... • each record is [k,b] • store [E(k), E(b)] • can search for records with k=E(x) Notes 3

  6. Issues • Hard to do range queries • Encryption not good • Better to use encryption that does not always generate same cyphertext k k E(k, random) E D simplification Notes 3

  7. How Do We Search Now? ??? search k=2 A: [E(2,dhe), E(b2)] [E(2, lkz), E(b4)] Q: k’=E(2) trusted processor dbms [E(1, abc), E(b1)] [E(2, dhe), E(b2)] [E(3, nft), E(b3)] [E(2, lkz), E(b4)] ... • each record is [k,b] • store [E(k, rand), E(b)] • can search for records with k=E(x,???)? Notes 3

  8. Solution? • Develop new decryption function: D(f(k1), E(k2, rand)) is true if k1=k2 Notes 3

  9. Solution? • Develop new decryption function: D(f(k1), E(k2, rand)) is true if k1=k2 Q: check if D(f(2),*) true search k=2 A: [E(2,dhe), E(b2)] [E(2, lkz), E(b4)] trusted processor dbms [E(1, abc), E(b1)] [E(2, dhe), E(b2)] [E(3, nft), E(b3)] [E(2, lkz), E(b4)] ... Notes 3

  10. Issues? • Cannot do non-equality predicates • Hard to build indexes Notes 3

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