Transciphering, Using FiLIP and TFHE for an Efficient Delegation of Computation

Hoffmann, Clément; Méaux, Pierrick; Ricosset, Thomas

doi:10.1007/978-3-030-65277-7_3

Cited by 19 publications

(8 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…But it is worth to notice that several other applications that use the GSW scheme could take advantage of the faster homomorphic operations of NGS. For example, by simply replacing GSW by NGS, one could speed up the transciphering for TFHE [20], or the homomorphic evaluation of maximum and minimum functions from [11], or the tree-based private information retrieval from [29].…”

Section: Our Techniques and Resultsmentioning

confidence: 99%

FINAL: Faster FHE Instantiated with NTRU and LWE

Bonte

Iliashenko

Park

et al. 2022

Lecture Notes in Computer Science

View full text Add to dashboard Cite

The NTRU problem is a promising candidate to build efficient Fully Homomorphic Encryption (FHE). However, all the existing proposals (e.g. LTV, YASHE) need so-called 'overstretched' parameters of NTRU to enable homomorphic operations. It was shown by Albrecht et al. (CRYPTO 2016) that these parameters are vulnerable against subfield lattice attacks. Based on a recent, more detailed analysis of the overstretched NTRU assumption by Ducas and van Woerden (ASIACRYPT 2021), we construct two FHE schemes whose NTRU parameters lie outside the overstretched range. The first scheme is based solely on NTRU and demonstrates competitive performance against the state-of-the-art FHE schemes including TFHE. Our second scheme, which is based on both the NTRU and LWE assumptions, outperforms TFHE with a 28% faster bootstrapping and 45% smaller bootstrapping and key-switching keys.

show abstract

Section: Our Techniques and Resultsmentioning

confidence: 99%

FINAL: Faster FHE Instantiated with NTRU and LWE

Bonte

Iliashenko

Park

et al. 2022

Lecture Notes in Computer Science

View full text Add to dashboard Cite

show abstract

“…The paradigm of FiLIP is recalled in Figure 2. We implemented the variant that is called FiLIP-144 in [HMR20], which consists in setting Z = 2 14 , z = 144 and f as the XOR-THR function XTHR [81,32,63] (that we recall in Definition 2). We note that those parameters of FiLIP-144 yield 128 bit security, following the analysis in [MCJS19].…”

Section: Filip Ciphermentioning

confidence: 99%

Towards Practical Transciphering for FHE with Setup Independent of the Plaintext Space

Méaux,

Park,

Pereira

2024

IACR CiC

Self Cite

View full text Add to dashboard Cite

Fully Homomorphic Encryption (FHE) is a powerful tool to achieve non-interactive privacy preserving protocols with optimal computation/communication complexity. However, the main disadvantage is that the actual communication cost (bandwidth) is high due to the large size of FHE ciphertexts. As a solution, a technique called transciphering (also known as Hybrid Homomorphic Encryption) was introduced to achieve almost optimal bandwidth for such protocols. However, all existing works require clients to fix a precision for the messages or a mathematical structure for the message space beforehand. It results in unwanted constraints on the plaintext size or underlying structure of FHE based applications. In this article, we introduce a new approach for transciphering which does not require fixed message precision decided by the client, for the first time. In more detail, a client uses any kind of FHE-friendly symmetric cipher for { 0 , 1 } to send its input data encrypted bit-by-bit, then the server can choose a precision p depending on the application and homomorphically transforms the encrypted bits into FHE ciphertexts encrypting integers in ℤ p . To illustrate our new technique, we evaluate a transciphering using FiLIP cipher and adapt the most practical homomorphic evaluation technique [CCS'22] to keep the practical latency. As a result, our proof-of-concept implementation for p from 2 2 to 2 8 takes only from 13 ms to 137 ms.

show abstract

“…These results have more implications for cryptographic applications: for example in the (improved) filter permutator context [2,32], for hybrid homomorphic encryption, there are efficient ways to evaluate symmetric functions (as illustrated in [33]), and doing one addition is cheap, therefore it is interesting to consider the best function in the S 0 -class of a filter function. In that case, for all contexts where adding one function is cheap, the hunt for optimized functions could be split into finding a cheap function to evaluate, and then determining the one with best cryptographic parameters in its T -class.…”

Section: Beyond Parameters In S 0 -Classesmentioning

confidence: 99%

S0-equivalent classes, a new direction to find better weightwise perfectly balanced functions, and more

Gini,

Méaux

2023

Preprint

Self Cite

View full text Add to dashboard Cite

We investigate the concept of S0 equivalent class, n-variable Boolean functions up to the addition of a symmetric function null in 0n and 1n, as a tool to study weightwise perfectly balanced functions. On the one hand we show that weightwise properties, such as being weightwise perfectly balanced, the weightwise nonlinearity and weightwise algebraic immunity, are invariant of these classes. On the other hand, we analyse the variation of global parameters inside the same class, showing for example that there is always a function with high degree, algebraic immunity, or nonlinearity in the S0 equivalent class of a function. Finally, we discuss how these results extend to other equivalence relations and their applications in cryptography MSC Classification: 94A60 , 94D10

show abstract

Transciphering, Using FiLIP and TFHE for an Efficient Delegation of Computation

Cited by 19 publications

References 28 publications

FINAL: Faster FHE Instantiated with NTRU and LWE

FINAL: Faster FHE Instantiated with NTRU and LWE

Towards Practical Transciphering for FHE with Setup Independent of the Plaintext Space

S0-equivalent classes, a new direction to find better weightwise perfectly balanced functions, and more

Contact Info

Product

Resources

About