Revision control
Copy as Markdown
Other Tools
/*
* Ed25519
* (C) 2017 Ribose Inc
*
* Based on the public domain code from SUPERCOP ref10 by
* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_ED25519_INT_H_
#define BOTAN_ED25519_INT_H_
#include <botan/internal/ed25519_fe.h>
#include <botan/loadstor.h>
namespace Botan {
inline uint64_t load_3(const uint8_t in[3])
{
return static_cast<uint64_t>(in[0]) |
(static_cast<uint64_t>(in[1]) << 8) |
(static_cast<uint64_t>(in[2]) << 16);
}
inline uint64_t load_4(const uint8_t* in)
{
return load_le<uint32_t>(in, 0);
}
template<size_t S, int64_t MUL=1>
inline void carry(int64_t& h0, int64_t& h1)
{
static_assert(S > 0 && S < 64, "Shift in range");
const int64_t X1 = (static_cast<int64_t>(1) << S);
const int64_t X2 = (static_cast<int64_t>(1) << (S - 1));
int64_t c = (h0 + X2) >> S;
h1 += c * MUL;
h0 -= c * X1;
}
template<size_t S>
inline void carry0(int64_t& h0, int64_t& h1)
{
static_assert(S > 0 && S < 64, "Shift in range");
const int64_t X1 = (static_cast<int64_t>(1) << S);
int64_t c = h0 >> S;
h1 += c;
h0 -= c * X1;
}
template<size_t S>
inline void carry0(int32_t& h0, int32_t& h1)
{
static_assert(S > 0 && S < 32, "Shift in range");
const int32_t X1 = (static_cast<int64_t>(1) << S);
int32_t c = h0 >> S;
h1 += c;
h0 -= c * X1;
}
inline void redc_mul(int64_t& s1,
int64_t& s2,
int64_t& s3,
int64_t& s4,
int64_t& s5,
int64_t& s6,
int64_t& X)
{
s1 += X * 666643;
s2 += X * 470296;
s3 += X * 654183;
s4 -= X * 997805;
s5 += X * 136657;
s6 -= X * 683901;
X = 0;
}
/*
ge means group element.
Here the group is the set of pairs (x,y) of field elements (see fe.h)
satisfying -x^2 + y^2 = 1 + d x^2y^2
where d = -121665/121666.
Representations:
ge_p3 (extended): (X:Y:Z:T) satisfying x=X/Z, y=Y/Z, XY=ZT
*/
typedef struct
{
fe X;
fe Y;
fe Z;
fe T;
} ge_p3;
int ge_frombytes_negate_vartime(ge_p3*, const uint8_t*);
void ge_scalarmult_base(uint8_t out[32], const uint8_t in[32]);
void ge_double_scalarmult_vartime(uint8_t out[32],
const uint8_t a[],
const ge_p3* A,
const uint8_t b[]);
/*
The set of scalars is \Z/l
where l = 2^252 + 27742317777372353535851937790883648493.
*/
void sc_reduce(uint8_t*);
void sc_muladd(uint8_t*, const uint8_t*, const uint8_t*, const uint8_t*);
}
#endif