{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T18:05:13Z","timestamp":1775585113775,"version":"3.50.1"},"reference-count":0,"publisher":"Universitatsbibliothek der Ruhr-Universitat Bochum","issue":"2","license":[{"start":{"date-parts":[[2025,3,4]],"date-time":"2025-03-04T00:00:00Z","timestamp":1741046400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["TCHES"],"abstract":"<jats:p>Making the most of TFHE programmable bootstrapping to evaluate functions or operators otherwise challenging to perform with only the native addition and multiplication of the scheme is a very active line of research. In this paper, we systematize this approach and apply it to build an 8-bit FHE processor abstraction, i.e., a software entity that works over FHE-encrypted 8-bit data and presents itself to the programmer by means of a conventional-looking assembly instruction set. In doing so, we provide several homomorphic LookUp Table (LUT) dereferencing operators based on variants of the tree-based method and show that they are the most efficient option for manipulating encryptions of 8-bit data (optimally represented as two basis 16 digits). We then systematically apply this approach over a set of around 50 instructions, including, notably, conditional assignments, divisions, or fixed-point arithmetic operations. We further test the approach on several simple algorithms, including the execution of a neuron with a sigmoid activation function with 16-bit precision. We conclude the paper by comparing our work to the FHE compilers available in the state of the art. Finally, this work reveals that a very limited set of functional bootstrapping patterns is versatile and efficient enough to achieve general-purpose FHE computations beyond the boolean circuit approach. As such, these patterns may be an appropriate target for further works on advanced software optimizations or hardware implementations.<\/jats:p>","DOI":"10.46586\/tches.v2025.i2.535-578","type":"journal-article","created":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T10:28:54Z","timestamp":1741170534000},"page":"535-578","source":"Crossref","is-referenced-by-count":5,"title":["Designing a General-Purpose 8-bit (T)FHE Processor Abstraction"],"prefix":"10.46586","volume":"2025","author":[{"given":"Daphn\u00e9","family":"Trama","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aymen","family":"Boudguiga","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pierre-Emmanuel","family":"Clet","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Renaud","family":"Sirdey","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicolas","family":"Ye","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"25480","published-online":{"date-parts":[[2025,3,4]]},"container-title":["IACR Transactions on Cryptographic Hardware and Embedded Systems"],"original-title":[],"link":[{"URL":"https:\/\/tches.iacr.org\/index.php\/TCHES\/article\/download\/12057\/11901","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/tches.iacr.org\/index.php\/TCHES\/article\/download\/12057\/11901","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T10:28:54Z","timestamp":1741170534000},"score":1,"resource":{"primary":{"URL":"https:\/\/tches.iacr.org\/index.php\/TCHES\/article\/view\/12057"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,4]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2025,3,4]]}},"URL":"https:\/\/doi.org\/10.46586\/tches.v2025.i2.535-578","relation":{},"ISSN":["2569-2925"],"issn-type":[{"value":"2569-2925","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,4]]}}}