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Re:Intel to Build Silicon for Fully Homomorphic Encryption by bawolff on Tuesday March 09, 2021 @12:09AM (#26395595)
FHE is semantically secure against chosen plaintext attacks. (The gentry latice scheme paper claims it is semantically secure against chosen plaintext attacks [1])

If i understand that correctly, it means that when you encrypt a value, you always get a different value, even if the plaintext is the same.

So how would the attacker observe that value 7 and 12 are the same without decrypting the value?

[1] https://www.google.com/url?sa=t&source=web&rct=j&url=https:/...

P.s. are you maybe confusing FHE with deterministic encryption or order-preserving-encryption which is sometimes used in "encrypted" (scare quotes because they're pretty bad) db products that still want to allow queries on encrypted data. That's a totally different thing with much much weaker security garuntees.

Re:Intel to Build Silicon for Fully Homomorphic Encryption by littlestymaar on Tuesday March 09, 2021 @01:06AM (#26395919)
Honestly, I don't understand how you can get downvoted for this answer. The GP should be downvoted in oblivion, because it obviously doesn't know what it's talking about, yet you are the greyed one…

If people don't believe the parent post and would like to see a visual “proof” of it, here is the (abbreviated) ciphertext for same value (`true`) encrypted by [TFHE](https://github.com/tfhe/tfhe), note how these aren't the same:

{ coefficients: [-224220402, 1267713220, 372943361, 263858338, -370546283, -605917751, -1924979310, -1572775794, 1846572795, -468768480, -290510339, -915978400, -1364310315, 809081884, -1495989601, -331539817, -1453231071, 404566454, 495420049, -879411073, 830751792, -517575314, 1556751889, 443973073, 1944290005, 674176195, -2141487034, -317403947, -460501881, -530948496, -1701307365, -1131020764, -951177975, 185735343, -607301526, -1413023671, -927580822, -1519370777, -867508577, 1783197541, -1563558893, 1077184331, 1711379115, 1493923712, 1553459001, -1181497038, 2076454627, 2090667603, -1811778643, -1964586812, -1514194032, 1847333213, -29937879, 1408366270, -246399878, -2100573013, 143332974, 355615400, -1746332080, 1803753774, 1010929751, -178538162, 2019489654, -1762380579, 1676883032, 855666812, 2078455615, 1070127391, -310916718, 1972027124, 1145751265, 1391734199, …], b: -362940425, current_variance: 0.0000000009313225746154785 }

{ coefficients: [-297806840, -994586634, 304850282, 863793687, 1840210042, -1105546555, -1110462781, 858561202, 1572862702, -1414807433, 925868178, -2022139768, 1977503124, -1355884545, 252233845, -607580470, -1640661899, 184197878, 175367248, -1883040938, -1452285303, 2135910408, 1848643984, 277669753, 1205220991, -1010438927, 344717140, -616704798, 617000592, -706461456, -1674056437, -1108542319, 1209547087, -1275731206, -1050202170, 1804450949, -212790115, 1603633119, 1581631548, 891985869, -767711288, 1662132229, -488697271, 1729020643, 68369628, 594815617, -697565685, -1119636178, -1069556471, 668091191, 2058655289, -965364559, -428300746, 1288771675, -1291673545, -1936980021, 1344393745, -566147990, -2017181358, -876369855, 1202714564, 279954504, 1954812679, -121935512, 1508624251, 1746889815, 10036320, -694130814, 1749036054, -350031511, 856310504, -486108325, 447226889, -108777191, 1323665880, 819541960, 441166350, -934866202, 837730330, 281902593, -1870154550, 963192542, 649262920, -2012432624, 1553637232, 627237492, 616166507, 781074188, 44864017, -1911286875, -1429302424, -1054092570, -1620457762, 641734226, 1629006914, 1365659737, 360668934, -874923908, …], b: 27536240, current_variance: 0.0000000009313225746154785 }