Files
MP-SPDZ/Math/modp.h
Marcel Keller 6cc3fccef0 Maintenance.
2023-05-09 14:50:53 +10:00

198 lines
6.1 KiB
C++

#ifndef _Modp
#define _Modp
/*
* Currently we only support an GMP based implementation.
*
* What ever is type-def'd to bigint is assumed to have
* operator overloading for all standard operators, has
* comparison operations and istream/ostream operators >>/<<.
*
* All "integer" operations will be done using operator notation
* all "modp" operations should be done using the function calls
* below (interchange with Montgomery arithmetic).
*
*/
#include "Tools/octetStream.h"
#include "Tools/random.h"
#include "Math/bigint.h"
#include "Math/Zp_Data.h"
template<int L>
class modp_
{
mp_limb_t x[L];
public:
static const int MAX_N_BITS = 64 * L;
static const int N_LIMBS = L;
// NEXT FUNCTION IS FOR DEBUG PURPOSES ONLY
mp_limb_t get_limb(int i) const { return x[i]; }
// use mem* functions instead of mpn_*, so the compiler can optimize
modp_()
{ avx_memzero(x, sizeof(x)); }
template<int M>
modp_(const modp_<M>& other)
{
inline_mpn_copyi(x, other.get(), min(L, M));
if (L > M)
inline_mpn_zero(x + M, L - M);
}
template<int X, int M>
modp_(const gfp_<X, M>& other, const Zp_Data& ZpD) :
modp_()
{
assert(other.get_ZpD() == ZpD);
assert(M <= L);
inline_mpn_copyi(x, other.get().get(), M);
}
template<int X, int M>
modp_(const gfpvar_<X, M>& other, const Zp_Data& ZpD) :
modp_()
{
if (other.get_ZpD() == ZpD)
*this = other.get();
else
to_modp(*this, bigint(other), ZpD);
}
const mp_limb_t* get() const { return x; }
void assign(const void* buffer, int t) { memcpy(x, buffer, t * sizeof(mp_limb_t)); }
void convert(const mp_limb_t* source, mp_size_t size, const Zp_Data& ZpD,
bool negative = false);
void convert_destroy(bigint& source, const Zp_Data& ZpD);
void convert_destroy(int source, const Zp_Data& ZpD) { to_modp(*this, source, ZpD); }
template<int M>
void convert_destroy(const fixint<M>& source, const Zp_Data& ZpD);
void zero_overhang(const Zp_Data& ZpD);
void randomize(PRNG& G, const Zp_Data& ZpD);
// Pack and unpack in native format
// i.e. Dont care about conversion to human readable form
// i.e. When we do montgomery we dont care about decoding
void pack(octetStream& o,const Zp_Data& ZpD) const;
void unpack(octetStream& o,const Zp_Data& ZpD);
void pack(octetStream& o) const;
void unpack(octetStream& o);
bool operator==(const modp_& other) const { return 0 == mpn_cmp(x, other.x, L); }
bool operator!=(const modp_& other) const { return not (*this == other); }
/**********************************
* Modp Operations *
**********************************/
// Convert representation to and from a modp number
void to_bigint(bigint& ans,const Zp_Data& ZpD,bool reduce=true) const;
template<int M>
void to_bigint(bigint& ans,const Zp_Data& ZpD,bool reduce=true) const;
template<int T>
void mul(const modp_& x, const modp_& y, const Zp_Data& ZpD);
template<int M> friend void to_modp(modp_<M>& ans,int x,const Zp_Data& ZpD);
template<int M> friend void to_modp(modp_<M>& ans,const mpz_class& x,const Zp_Data& ZpD);
modp_ add(const modp_& other, const Zp_Data& ZpD) const;
modp_ sub(const modp_& other, const Zp_Data& ZpD) const;
modp_ mul(const modp_& other, const Zp_Data& ZpD) const;
friend void Add(modp_& ans,const modp_& x,const modp_& y,const Zp_Data& ZpD)
{ ZpD.Add(ans.x, x.x, y.x); }
template<int M> friend void Sub(modp_<M>& ans,const modp_<M>& x,const modp_<M>& y,const Zp_Data& ZpD);
template<int M> friend void Mul(modp_<M>& ans,const modp_<M>& x,const modp_<M>& y,const Zp_Data& ZpD);
template<int M> friend void Sqr(modp_<M>& ans,const modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend void Negate(modp_<M>& ans,const modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend void Inv(modp_<M>& ans,const modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend void Power(modp_<M>& ans,const modp_<M>& x,int exp,const Zp_Data& ZpD);
template<int M> friend void Power(modp_<M>& ans,const modp_<M>& x,const bigint& exp,const Zp_Data& ZpD);
template<int M> friend void assignOne(modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend void assignZero(modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend bool isZero(const modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend bool isOne(const modp_<M>& x,const Zp_Data& ZpD);
template<int M> friend bool areEqual(const modp_<M>& x,const modp_<M>& y,const Zp_Data& ZpD);
// Input and output from a stream
// - Can do in human or machine only format (later should be faster)
// - If human output appends a space to help with reading
// and also convert back/forth from Montgomery if needed
void output(ostream& s,const Zp_Data& ZpD,bool human) const;
void input(istream& s,const Zp_Data& ZpD,bool human);
template<int X, int K>
friend class gfp_;
};
typedef modp_<MAX_MOD_SZ> modp;
template<int L>
inline void modp_<L>::pack(octetStream& o,const Zp_Data& ZpD) const
{
o.append((octet*) x,ZpD.t*sizeof(mp_limb_t));
}
template<int L>
void assignZero(modp_<L>& x,const Zp_Data& ZpD)
{
if (sizeof(x.x) <= 3 * 16)
// use memset to allow the compiler to optimize
// if x.x is at most 3*128 bits
avx_memzero(x.x, sizeof(x.x));
else
inline_mpn_zero(x.x, ZpD.get_t());
}
template<int L>
inline void Sub(modp_<L>& ans,const modp_<L>& x,const modp_<L>& y,const Zp_Data& ZpD)
{
ZpD.Sub(ans.x, x.x, y.x);
}
template<int L>
inline void Mul(modp_<L>& ans,const modp_<L>& x,const modp_<L>& y,const Zp_Data& ZpD)
{
if (ZpD.montgomery)
{ ZpD.Mont_Mult_max(ans.x,x.x,y.x,L); }
else
{ //ans.x=(x.x*y.x)%ZpD.pr;
mp_limb_t aa[2*L],q[2*L];
mpn_mul_n(aa,x.x,y.x,ZpD.t);
mpn_tdiv_qr(q,ans.x,0,aa,2*ZpD.t,ZpD.prA,ZpD.t);
}
}
template<int L>
template<int T>
inline void modp_<L>::mul(const modp_<L>& x, const modp_<L>& y, const Zp_Data& ZpD)
{
if (ZpD.montgomery)
ZpD.Mont_Mult_<T>(this->x, x.x, y.x);
else
Mul<L>(*this, x, y, ZpD);
}
template<int L>
void to_bigint(bigint& ans,const modp_<L>& x,const Zp_Data& ZpD,bool reduce=true)
{
x.to_bigint(ans, ZpD, reduce);
}
#endif