Skip to content

Commit

Permalink
Replaces unsafe conversion by LittleEndian encoding.
Browse files Browse the repository at this point in the history
  • Loading branch information
@armfazh
armfazh committed Jun 2, 2020
1 parent 9beea96 commit a029187
Show file tree
Hide file tree
Showing 3 changed files with 236 additions and 129 deletions.
177 changes: 108 additions & 69 deletions math/fp25519/fp_generic.go
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package fp25519

import (
"encoding/binary"
"math/bits"
"unsafe"
)
Expand Down Expand Up @@ -34,37 +35,59 @@ func cswapGeneric(x, y *Elt, n uint) {
}

func addGeneric(z, x, y *Elt) {
zz := (*elt64)(unsafe.Pointer(z))
xx := (*elt64)(unsafe.Pointer(x))
yy := (*elt64)(unsafe.Pointer(y))
x0 := binary.LittleEndian.Uint64(x[0*8 : 1*8])
x1 := binary.LittleEndian.Uint64(x[1*8 : 2*8])
x2 := binary.LittleEndian.Uint64(x[2*8 : 3*8])
x3 := binary.LittleEndian.Uint64(x[3*8 : 4*8])

z0, c0 := bits.Add64(xx[0], yy[0], 0)
z1, c1 := bits.Add64(xx[1], yy[1], c0)
z2, c2 := bits.Add64(xx[2], yy[2], c1)
z3, c3 := bits.Add64(xx[3], yy[3], c2)
y0 := binary.LittleEndian.Uint64(y[0*8 : 1*8])
y1 := binary.LittleEndian.Uint64(y[1*8 : 2*8])
y2 := binary.LittleEndian.Uint64(y[2*8 : 3*8])
y3 := binary.LittleEndian.Uint64(y[3*8 : 4*8])

z0, c0 := bits.Add64(x0, y0, 0)
z1, c1 := bits.Add64(x1, y1, c0)
z2, c2 := bits.Add64(x2, y2, c1)
z3, c3 := bits.Add64(x3, y3, c2)

z0, c0 = bits.Add64(z0, (-c3)&38, 0)
zz[1], c1 = bits.Add64(z1, 0, c0)
zz[2], c2 = bits.Add64(z2, 0, c1)
zz[3], c3 = bits.Add64(z3, 0, c2)
zz[0], _ = bits.Add64(z0, (-c3)&38, 0)
z1, c1 = bits.Add64(z1, 0, c0)
z2, c2 = bits.Add64(z2, 0, c1)
z3, c3 = bits.Add64(z3, 0, c2)
z0, _ = bits.Add64(z0, (-c3)&38, 0)

binary.LittleEndian.PutUint64(z[0*8:1*8], z0)
binary.LittleEndian.PutUint64(z[1*8:2*8], z1)
binary.LittleEndian.PutUint64(z[2*8:3*8], z2)
binary.LittleEndian.PutUint64(z[3*8:4*8], z3)
}

func subGeneric(z, x, y *Elt) {
zz := (*elt64)(unsafe.Pointer(z))
xx := (*elt64)(unsafe.Pointer(x))
yy := (*elt64)(unsafe.Pointer(y))
x0 := binary.LittleEndian.Uint64(x[0*8 : 1*8])
x1 := binary.LittleEndian.Uint64(x[1*8 : 2*8])
x2 := binary.LittleEndian.Uint64(x[2*8 : 3*8])
x3 := binary.LittleEndian.Uint64(x[3*8 : 4*8])

y0 := binary.LittleEndian.Uint64(y[0*8 : 1*8])
y1 := binary.LittleEndian.Uint64(y[1*8 : 2*8])
y2 := binary.LittleEndian.Uint64(y[2*8 : 3*8])
y3 := binary.LittleEndian.Uint64(y[3*8 : 4*8])

z0, c0 := bits.Sub64(xx[0], yy[0], 0)
z1, c1 := bits.Sub64(xx[1], yy[1], c0)
z2, c2 := bits.Sub64(xx[2], yy[2], c1)
z3, c3 := bits.Sub64(xx[3], yy[3], c2)
z0, c0 := bits.Sub64(x0, y0, 0)
z1, c1 := bits.Sub64(x1, y1, c0)
z2, c2 := bits.Sub64(x2, y2, c1)
z3, c3 := bits.Sub64(x3, y3, c2)

z0, c0 = bits.Sub64(z0, (-c3)&38, 0)
zz[1], c1 = bits.Sub64(z1, 0, c0)
zz[2], c2 = bits.Sub64(z2, 0, c1)
zz[3], c3 = bits.Sub64(z3, 0, c2)
zz[0], _ = bits.Sub64(z0, (-c3)&38, 0)
z1, c1 = bits.Sub64(z1, 0, c0)
z2, c2 = bits.Sub64(z2, 0, c1)
z3, c3 = bits.Sub64(z3, 0, c2)
z0, _ = bits.Sub64(z0, (-c3)&38, 0)

binary.LittleEndian.PutUint64(z[0*8:1*8], z0)
binary.LittleEndian.PutUint64(z[1*8:2*8], z1)
binary.LittleEndian.PutUint64(z[2*8:3*8], z2)
binary.LittleEndian.PutUint64(z[3*8:4*8], z3)
}

func addsubGeneric(x, y *Elt) {
Expand All @@ -75,30 +98,35 @@ func addsubGeneric(x, y *Elt) {
}

func mulGeneric(z, x, y *Elt) {
zz := (*elt64)(unsafe.Pointer(z))
xx := (*elt64)(unsafe.Pointer(x))
yy := (*elt64)(unsafe.Pointer(y))
x0 := binary.LittleEndian.Uint64(x[0*8 : 1*8])
x1 := binary.LittleEndian.Uint64(x[1*8 : 2*8])
x2 := binary.LittleEndian.Uint64(x[2*8 : 3*8])
x3 := binary.LittleEndian.Uint64(x[3*8 : 4*8])

y0 := binary.LittleEndian.Uint64(y[0*8 : 1*8])
y1 := binary.LittleEndian.Uint64(y[1*8 : 2*8])
y2 := binary.LittleEndian.Uint64(y[2*8 : 3*8])
y3 := binary.LittleEndian.Uint64(y[3*8 : 4*8])

x0, x1, x2, x3 := xx[0], xx[1], xx[2], xx[3]
yi := yy[0]
yi := y0
h0, l0 := bits.Mul64(x0, yi)
h1, l1 := bits.Mul64(x1, yi)
h2, l2 := bits.Mul64(x2, yi)
h3, l3 := bits.Mul64(x3, yi)

zz[0] = l0
z0 := l0
a0, c0 := bits.Add64(h0, l1, 0)
a1, c1 := bits.Add64(h1, l2, c0)
a2, c2 := bits.Add64(h2, l3, c1)
a3, _ := bits.Add64(h3, 0, c2)

yi = yy[1]
yi = y1
h0, l0 = bits.Mul64(x0, yi)
h1, l1 = bits.Mul64(x1, yi)
h2, l2 = bits.Mul64(x2, yi)
h3, l3 = bits.Mul64(x3, yi)

zz[1], c0 = bits.Add64(a0, l0, 0)
z1, c0 := bits.Add64(a0, l0, 0)
h0, c1 = bits.Add64(h0, l1, c0)
h1, c2 = bits.Add64(h1, l2, c1)
h2, c3 := bits.Add64(h2, l3, c2)
Expand All @@ -109,13 +137,13 @@ func mulGeneric(z, x, y *Elt) {
a2, c2 = bits.Add64(a3, h2, c1)
a3, _ = bits.Add64(0, h3, c2)

yi = yy[2]
yi = y2
h0, l0 = bits.Mul64(x0, yi)
h1, l1 = bits.Mul64(x1, yi)
h2, l2 = bits.Mul64(x2, yi)
h3, l3 = bits.Mul64(x3, yi)

zz[2], c0 = bits.Add64(a0, l0, 0)
z2, c0 := bits.Add64(a0, l0, 0)
h0, c1 = bits.Add64(h0, l1, c0)
h1, c2 = bits.Add64(h1, l2, c1)
h2, c3 = bits.Add64(h2, l3, c2)
Expand All @@ -126,31 +154,32 @@ func mulGeneric(z, x, y *Elt) {
a2, c2 = bits.Add64(a3, h2, c1)
a3, _ = bits.Add64(0, h3, c2)

yi = yy[3]
yi = y3
h0, l0 = bits.Mul64(x0, yi)
h1, l1 = bits.Mul64(x1, yi)
h2, l2 = bits.Mul64(x2, yi)
h3, l3 = bits.Mul64(x3, yi)

zz[3], c0 = bits.Add64(a0, l0, 0)
z3, c0 := bits.Add64(a0, l0, 0)
h0, c1 = bits.Add64(h0, l1, c0)
h1, c2 = bits.Add64(h1, l2, c1)
h2, c3 = bits.Add64(h2, l3, c2)
h3, _ = bits.Add64(h3, 0, c3)

b4, c0 := bits.Add64(a1, h0, 0)
b5, c1 := bits.Add64(a2, h1, c0)
b6, c2 := bits.Add64(a3, h2, c1)
b7, _ := bits.Add64(0, h3, c2)
z4, c0 := bits.Add64(a1, h0, 0)
z5, c1 := bits.Add64(a2, h1, c0)
z6, c2 := bits.Add64(a3, h2, c1)
z7, _ := bits.Add64(0, h3, c2)

red64(zz, &elt64{b4, b5, b6, b7})
red64(z, z0, z1, z2, z3, z4, z5, z6, z7)
}

func sqrGeneric(z, x *Elt) {
zz := (*elt64)(unsafe.Pointer(z))
xx := (*elt64)(unsafe.Pointer(x))
x0 := binary.LittleEndian.Uint64(x[0*8 : 1*8])
x1 := binary.LittleEndian.Uint64(x[1*8 : 2*8])
x2 := binary.LittleEndian.Uint64(x[2*8 : 3*8])
x3 := binary.LittleEndian.Uint64(x[3*8 : 4*8])

x0, x1, x2, x3 := xx[0], xx[1], xx[2], xx[3]
h0, a0 := bits.Mul64(x0, x1)
h1, l1 := bits.Mul64(x0, x2)
h2, l2 := bits.Mul64(x0, x3)
Expand Down Expand Up @@ -190,24 +219,24 @@ func sqrGeneric(z, x *Elt) {
b5, c4 = bits.Add64(b5, a4, c3)
b6, c5 = bits.Add64(b6, a5, c4)
b7, _ = bits.Add64(b7, a6, c5)
zz[0] = b0
zz[1] = b1
zz[2] = b2
zz[3] = b3
red64(zz, &elt64{b4, b5, b6, b7})

red64(z, b0, b1, b2, b3, b4, b5, b6, b7)
}

func modpGeneric(x *Elt) {
xx := (*elt64)(unsafe.Pointer(x))
x3 := xx[3]
x0 := binary.LittleEndian.Uint64(x[0*8 : 1*8])
x1 := binary.LittleEndian.Uint64(x[1*8 : 2*8])
x2 := binary.LittleEndian.Uint64(x[2*8 : 3*8])
x3 := binary.LittleEndian.Uint64(x[3*8 : 4*8])

// CX = C[255] ? 38 : 19
cx := uint64(19) << (x3 >> 63)
// PUT BIT 255 IN CARRY FLAG AND CLEAR
x3 &^= 1 << 63

x0, c0 := bits.Add64(xx[0], cx, 0)
x1, c1 := bits.Add64(xx[1], 0, c0)
x2, c2 := bits.Add64(xx[2], 0, c1)
x0, c0 := bits.Add64(x0, cx, 0)
x1, c1 := bits.Add64(x1, 0, c0)
x2, c2 := bits.Add64(x2, 0, c1)
x3, _ = bits.Add64(x3, 0, c2)

// TEST FOR BIT 255 AGAIN; ONLY TRIGGERED ON OVERFLOW MODULO 2^255-19
Expand All @@ -216,33 +245,43 @@ func modpGeneric(x *Elt) {
// CLEAR BIT 255
x3 &^= 1 << 63

xx[0], c0 = bits.Sub64(x0, cx, 0)
xx[1], c1 = bits.Sub64(x1, 0, c0)
xx[2], c2 = bits.Sub64(x2, 0, c1)
xx[3], _ = bits.Sub64(x3, 0, c2)
x0, c0 = bits.Sub64(x0, cx, 0)
x1, c1 = bits.Sub64(x1, 0, c0)
x2, c2 = bits.Sub64(x2, 0, c1)
x3, _ = bits.Sub64(x3, 0, c2)

binary.LittleEndian.PutUint64(x[0*8:1*8], x0)
binary.LittleEndian.PutUint64(x[1*8:2*8], x1)
binary.LittleEndian.PutUint64(x[2*8:3*8], x2)
binary.LittleEndian.PutUint64(x[3*8:4*8], x3)
}

func red64(z, h *elt64) {
h0, l0 := bits.Mul64(h[0], 38)
h1, l1 := bits.Mul64(h[1], 38)
h2, l2 := bits.Mul64(h[2], 38)
h3, l3 := bits.Mul64(h[3], 38)
func red64(z *Elt, x0, x1, x2, x3, x4, x5, x6, x7 uint64) {
h0, l0 := bits.Mul64(x4, 38)
h1, l1 := bits.Mul64(x5, 38)
h2, l2 := bits.Mul64(x6, 38)
h3, l3 := bits.Mul64(x7, 38)

l1, c0 := bits.Add64(h0, l1, 0)
l2, c1 := bits.Add64(h1, l2, c0)
l3, c2 := bits.Add64(h2, l3, c1)
l4, _ := bits.Add64(h3, 0, c2)

l0, c0 = bits.Add64(l0, z[0], 0)
l1, c1 = bits.Add64(l1, z[1], c0)
l2, c2 = bits.Add64(l2, z[2], c1)
l3, c3 := bits.Add64(l3, z[3], c2)
l0, c0 = bits.Add64(l0, x0, 0)
l1, c1 = bits.Add64(l1, x1, c0)
l2, c2 = bits.Add64(l2, x2, c1)
l3, c3 := bits.Add64(l3, x3, c2)
l4, _ = bits.Add64(l4, 0, c3)

_, l4 = bits.Mul64(l4, 38)
l0, c0 = bits.Add64(l0, l4, 0)
z[1], c1 = bits.Add64(l1, 0, c0)
z[2], c2 = bits.Add64(l2, 0, c1)
z[3], c3 = bits.Add64(l3, 0, c2)
z[0], _ = bits.Add64(l0, (-c3)&38, 0)
z1, c1 := bits.Add64(l1, 0, c0)
z2, c2 := bits.Add64(l2, 0, c1)
z3, c3 := bits.Add64(l3, 0, c2)
z0, _ := bits.Add64(l0, (-c3)&38, 0)

binary.LittleEndian.PutUint64(z[0*8:1*8], z0)
binary.LittleEndian.PutUint64(z[1*8:2*8], z1)
binary.LittleEndian.PutUint64(z[2*8:3*8], z2)
binary.LittleEndian.PutUint64(z[3*8:4*8], z3)
}
14 changes: 9 additions & 5 deletions math/fp448/edgecases_test.go
View file
Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
package fp448

import (
"encoding/binary"
"math/big"
"testing"
"unsafe"

"github.com/cloudflare/circl/internal/conv"
"github.com/cloudflare/circl/internal/test"
Expand Down Expand Up @@ -73,11 +73,15 @@ func ecRed64(t *testing.T) {
two224plus1.Add(two224plus1, big.NewInt(1)) // 2^224+1

var got, want Elt
var lo, hi elt64
for _, c := range cases {
var lo = *(*elt64)(unsafe.Pointer(&c[0*Size]))
var hi = *(*elt64)(unsafe.Pointer(&c[1*Size]))
red64(&lo, &hi)
got = *(*Elt)(unsafe.Pointer(&lo))
cLo := c[0*Size:]
cHi := c[1*Size:]
for i := range lo {
lo[i] = binary.LittleEndian.Uint64(cLo[i*8 : (i+1)*8])
hi[i] = binary.LittleEndian.Uint64(cHi[i*8 : (i+1)*8])
}
red64(&got, &lo, &hi)

tt := conv.BytesLe2BigInt(c[:2*Size])

Expand Down
Loading

0 comments on commit a029187

Please sign in to comment.