730 likes | 849 Views
A Brief Story of Computing on Private Data. Ten H Lai Ohio State University. Agenda. Computing on private data Fully homomorphic encryption (FHE) Gentry’s bootstrapping theorem Our result. FHE: The Holy Grail of Cryptography. Cloud Computing. Networks. Applications. Storages.
E N D
A Brief Story of Computing on Private Data Ten H Lai Ohio State University
Agenda • Computing on private data • Fully homomorphic encryption (FHE) • Gentry’s bootstrapping theorem • Our result
Cloud Computing Networks Applications Storages Servers
天上有多少星星 城裡有多少姑娘 但人間只有一個妳 天上只有一顆月亮
Cloud Computing Encrypt Cloud server Internet
Computing on private data Encrypt Cloud server Internet
Computing on private data Cloud • A question proposed by Rivest, Aldeman, Dertouzos in 1978 (one year after RSA was invented).
Evaluate Decrypt skA Decrypt m m m m encrypted under a pink key pkA
Evaluate Decrypt skA Decrypt m m skA Encrypt under a blue key pkB Evaluate Decrypt m m
NAND-augmented Decrypt circuit: skA skA Decrypt NAND m1 m1NANDm2 Decrypt m2
Evaluate skA c1 skA c2 Decrypt NAND m1 m1NANDm2 Decrypt fresh m2
Under a pink key PKA Under a blue key PKB m1 m1NANDm2 m2 fresh skA 23
m1 m1NANDm2 m2 Increased noise 24
skA m1 m2 m1NANDm2 Evaluate Decrypt-NAND m1NANDm2 (m1NAND m2) NAND (m3NAND m4) Evaluate Decrypt-NAND skB skA m3 m4 m3NANDm4 Evaluate Decrypt-NAND m3NANDm4
skA m1 m2 m1NANDm2 Evaluate Decrypt-NAND m1NANDm2 (m1NAND m2) NAND (m3NAND m4) Evaluate Decrypt-NAND skB skA m3 m4 m3NANDm4 Evaluate Decrypt-NAND m3NANDm4
NAND Decrypt Decrypt
Encryption key • Evaluation key • Decryption key
Decrypt Decrypt
Encryption key • Evaluation key • Decryption key
level d level 1 … Decrypt circuits
… Decrypt circuits
Encryption key • Evaluation key • Decryption key
NAND Decrypt Decrypt
Decryption algorithm Secret-key independent , Computationally intensive, Done with encryption Secret-keydependent