fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth > Class Template Reference

2-party VDPF scheme. More...

Classes
struct	Cw
	Correction word. More...

Public Member Functions
int	Gen (Cw cws[], cuda::std::array< int4, 4 > &cs, int4 &ocw, cuda::std::span< const int4, 2 > s0s, In a, int4 b_buf)
	Key generation method.
cuda::std::array< int4, 4 >	Eval (bool b, int4 s0, cuda::std::span< const Cw > cws, cuda::std::span< const int4, 4 > cs, int4 ocw, In x, int4 &y)
	Evaluation method.
void	Prove (cuda::std::span< const cuda::std::array< int4, 4 > > pi_tildes, cuda::std::span< const int4, 4 > cs, cuda::std::array< int4, 4 > &pi)
	Proof accumulation method.
void	EvalAll (bool b, int4 s0, cuda::std::span< const Cw > cws, cuda::std::span< const int4, 4 > cs, int4 ocw, cuda::std::span< int4 > ys, cuda::std::array< int4, 4 > &pi)
	Full domain evaluation method.

Static Public Member Functions
static bool	Verify (cuda::std::span< const int4, 4 > pi0, cuda::std::span< const int4, 4 > pi1)
	Verification method.

Public Attributes
Prg	prg
XorHash	xor_hash
Hash	hash

Detailed Description

template<int in_bits, typename Group, typename Prg, typename XorHash, typename Hash, typename In = uint, int par_depth = -1>
requires ((std::is_unsigned_v<In> || std::is_same_v<In, __uint128_t>) && in_bits <= sizeof(In) * 8 && Groupable<Group> && Prgable<Prg, 2> && XorHashable<XorHash> && Hashable<Hash>)
class fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >

2-party VDPF scheme.

Template Parameters

in_bits	Input domain bit size.
Group	Type for the output domain. See Groupable.
Prg	See Prgable.
XorHash	See XorHashable. Paper's \(H\): maps \((x, s)\) to \(4\lambda\) bits.
Hash	See Hashable. Paper's \(H'\): maps \(4\lambda\) bits to \(2\lambda\) bits.
In	Type for the input domain. From uint8_t to __uint128_t.
par_depth	-1 is to use ceil(log(num of threads)), which should be good enough. Only EvalAll() uses it. See EvalAll() for details.

Member Function Documentation

Eval()

template<int in_bits, typename Group , typename Prg , typename XorHash , typename Hash , typename In = uint, int par_depth = -1>

cuda::std::array< int4, 4 > fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >::Eval ( bool  b, int4  s0, cuda::std::span< const Cw >  cws, cuda::std::span< const int4, 4 >  cs, int4  ocw, In  x, int4 &  y  )

inline

Evaluation method.

Parameters

b	Party index. False for 0 and true for 1. \(i\).
s0	Initial seed of the party.
cws	Returned by Gen(). Size must be in_bits.
cs	Returned by Gen().
ocw	Returned by Gen().
x	Evaluated input. \(x\).
y	Output share written here. \(y_{i,x}\).

Returns

Corrected per-point hash ( \(\correct(\tilde\pi, cs, t)\)) for proof accumulation.

EvalAll()

template<int in_bits, typename Group , typename Prg , typename XorHash , typename Hash , typename In = uint, int par_depth = -1>

void fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >::EvalAll ( bool  b, int4  s0, cuda::std::span< const Cw >  cws, cuda::std::span< const int4, 4 >  cs, int4  ocw, cuda::std::span< int4 >  ys, cuda::std::array< int4, 4 > &  pi  )

inline

Full domain evaluation method.

Evaluate the key on each input, i.e., 0b00...0 - 0b11...1. Store the outputs sequentially and accumulate the proof.

b, s0, cws, cs, ocw are the same as the ones in Eval().

Parameters

ys	Pre-allocated output array. Its size must be at least 2 ** in_bits.
pi	Proof output.

Support parallel using OpenMP for the tree traversal phase. The task is divided to 2 ** par_depth parallel sub-tasks with the equal workloads. par_depth = -1: use ceil(log(num of threads)). par_depth = 0: no parallelism, i.e., sequential execution.

Gen()

template<int in_bits, typename Group , typename Prg , typename XorHash , typename Hash , typename In = uint, int par_depth = -1>

int fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >::Gen ( Cw  cws[], cuda::std::array< int4, 4 > &  cs, int4 &  ocw, cuda::std::span< const int4, 2 >  s0s, In  a, int4  b_buf  )

inline

Key generation method.

Parameters

cws	Pre-allocated array of Cw as returns. The array size must be in_bits.
cs	Correction seed output ( \(4\lambda\) bits).
ocw	Output correction word output.
s0s	2 initial seeds. Users can randomly sample them.
a	\(a\).
b_buf	\(b\). Will be clamped and converted to the group element.

Returns

0 on success, 1 if \(t_0 = t_1\) at the end (caller should resample seeds and retry).

The key for party i consists of cws + cs + ocw + s0s[i].

Prove()

template<int in_bits, typename Group , typename Prg , typename XorHash , typename Hash , typename In = uint, int par_depth = -1>

void fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >::Prove ( cuda::std::span< const cuda::std::array< int4, 4 > >  pi_tildes, cuda::std::span< const int4, 4 >  cs, cuda::std::array< int4, 4 > &  pi  )

inline

Proof accumulation method.

Accumulates corrected per-point hashes (from Eval()) into a single proof.

Parameters

pi_tildes	Corrected per-point hashes returned by Eval().
cs	Returned by Gen().
pi	Proof output.

Verify()

template<int in_bits, typename Group , typename Prg , typename XorHash , typename Hash , typename In = uint, int par_depth = -1>

static bool fss::Vdpf< in_bits, Group, Prg, XorHash, Hash, In, par_depth >::Verify ( cuda::std::span< const int4, 4 >  pi0, cuda::std::span< const int4, 4 >  pi1  )

inlinestatic

Verification method.

Returns

True if proofs match (Accept), false otherwise (Reject).

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The documentation for this class was generated from the following file:

• include/fss/vdpf.cuh