Improved Bootstrapping for Approximate Homomorphic Encryption
| Autor: | Ilaria Chillotti, Hao Chen, Yongsoo Song |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0303 health sciences
Chebyshev polynomials Approximation theory Computer science business.industry Homomorphic encryption Bootstrapping (linguistics) Plaintext 02 engineering and technology Encryption 03 medical and health sciences symbols.namesake Ciphertext 0202 electrical engineering electronic engineering information engineering Taylor series symbols 020201 artificial intelligence & image processing business Algorithm Computer Science::Cryptography and Security 030304 developmental biology |
| Zdroj: | Advances in Cryptology – EUROCRYPT 2019 ISBN: 9783030176556 EUROCRYPT (2) |
| DOI: | 10.1007/978-3-030-17656-3_2 |
| Popis: | Since Cheon et al. introduced a homomorphic encryption scheme for approximate arithmetic (Asiacrypt ’17), it has been recognized as suitable for important real-life usecases of homomorphic encryption, including training of machine learning models over encrypted data. A follow up work by Cheon et al. (Eurocrypt ’18) described an approximate bootstrapping procedure for the scheme. In this work, we improve upon the previous bootstrapping result. We improve the amortized bootstrapping time per plaintext slot by two orders of magnitude, from \(\sim \)1 s to \(\sim \)0.01 s. To achieve this result, we adopt a smart level-collapsing technique for evaluating DFT-like linear transforms on a ciphertext. Also, we replace the Taylor approximation of the sine function with a more accurate and numerically stable Chebyshev approximation, and design a modified version of the Paterson-Stockmeyer algorithm for fast evaluation of Chebyshev polynomials over encrypted data. |
| Databáze: | OpenAIRE |
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