forked from dedis/kyber
/
scalar.go
2266 lines (2106 loc) · 51.4 KB
/
scalar.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package edwards25519
import (
"crypto/cipher"
"crypto/subtle"
"encoding/hex"
"errors"
"io"
"math/big"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/group/internal/marshalling"
"go.dedis.ch/kyber/v3/group/mod"
"go.dedis.ch/kyber/v3/util/random"
)
// This code is a port of the public domain, "ref10" implementation of ed25519
// from SUPERCOP. More information at https://bench.cr.yp.to/supercop.html.
// The scalars are GF(2^252 + 27742317777372353535851937790883648493).
var marshalScalarID = [8]byte{'e', 'd', '.', 's', 'c', 'a', 'l', 'a'}
type scalar struct {
v [32]byte
}
// Equality test for two Scalars derived from the same Group
func (s *scalar) Equal(s2 kyber.Scalar) bool {
v1 := s.v[:]
v2 := s2.(*scalar).v[:]
return subtle.ConstantTimeCompare(v1, v2) != 0
}
// Set equal to another Scalar a
func (s *scalar) Set(a kyber.Scalar) kyber.Scalar {
s.v = a.(*scalar).v
return s
}
// Clone returns a duplicate of the scalar s.
func (s *scalar) Clone() kyber.Scalar {
s2 := *s
return &s2
}
func (s *scalar) setInt(i *mod.Int) kyber.Scalar {
b := i.LittleEndian(32, 32)
copy(s.v[:], b)
return s
}
// SetInt64 sets the scalar to a small integer value.
func (s *scalar) SetInt64(v int64) kyber.Scalar {
return s.setInt(mod.NewInt64(v, primeOrder))
}
func (s *scalar) toInt() *mod.Int {
return mod.NewIntBytes(s.v[:], primeOrder, mod.LittleEndian)
}
// Set to the additive identity (0)
func (s *scalar) Zero() kyber.Scalar {
s.v = [32]byte{0}
return s
}
// Set to the multiplicative identity (1)
func (s *scalar) One() kyber.Scalar {
s.v = [32]byte{1}
return s
}
// Set to the modular sum of scalars a and b
func (s *scalar) Add(a, b kyber.Scalar) kyber.Scalar {
scAdd(&s.v, &a.(*scalar).v, &b.(*scalar).v)
return s
}
// Set to the modular difference a - b
func (s *scalar) Sub(a, b kyber.Scalar) kyber.Scalar {
scSub(&s.v, &a.(*scalar).v, &b.(*scalar).v)
return s
}
// Set to the modular negation of scalar a
func (s *scalar) Neg(a kyber.Scalar) kyber.Scalar {
var z scalar
z.Zero()
scSub(&s.v, &z.v, &a.(*scalar).v)
return s
}
// Set to the modular product of scalars a and b
func (s *scalar) Mul(a, b kyber.Scalar) kyber.Scalar {
scMul(&s.v, &a.(*scalar).v, &b.(*scalar).v)
return s
}
// Set to the modular division of scalar a by scalar b
func (s *scalar) Div(a, b kyber.Scalar) kyber.Scalar {
var i scalar
i.Inv(b)
scMul(&s.v, &a.(*scalar).v, &i.v)
return s
}
// Set to the modular inverse of scalar a
func (s *scalar) Inv(a kyber.Scalar) kyber.Scalar {
var res scalar
res.One()
ac := a.(*scalar)
// Modular inversion in a multiplicative group is a^(phi(m)-1) = a^-1 mod m
// Since m is prime, phi(m) = m - 1 => a^(m-2) = a^-1 mod m.
// The inverse is computed using the exponentation-and-square algorithm.
// Implementation is constant time regarding the value a, it only depends on
// the modulo.
for i := 255; i >= 0; i-- {
bit := lMinus2.Bit(i)
// square step
scMul(&res.v, &res.v, &res.v)
if bit == 1 {
// multiply step
scMul(&res.v, &res.v, &ac.v)
}
}
s.v = res.v
return s
}
// Set to a fresh random or pseudo-random scalar
func (s *scalar) Pick(rand cipher.Stream) kyber.Scalar {
i := mod.NewInt(random.Int(primeOrder, rand), primeOrder)
return s.setInt(i)
}
// SetBytes s to b, interpreted as a little endian integer.
func (s *scalar) SetBytes(b []byte) kyber.Scalar {
return s.setInt(mod.NewIntBytes(b, primeOrder, mod.LittleEndian))
}
// String returns the string representation of this scalar (fixed length of 32 bytes, little endian).
func (s *scalar) String() string {
b, _ := s.toInt().MarshalBinary()
for len(b) < 32 {
b = append(b, 0)
}
return hex.EncodeToString(b)
}
// Encoded length of this object in bytes.
func (s *scalar) MarshalSize() int {
return 32
}
// MarshalBinary returns the binary representation of this scalar.
func (s *scalar) MarshalBinary() ([]byte, error) {
return s.toInt().MarshalBinary()
}
// MarshalID returns the type tag used in encoding/decoding
func (s *scalar) MarshalID() [8]byte {
return marshalScalarID
}
// UnmarshalBinary reads the binary representation of a scalar.
func (s *scalar) UnmarshalBinary(buf []byte) error {
if len(buf) != 32 {
return errors.New("wrong size buffer")
}
copy(s.v[:], buf)
return nil
}
// MarshalTo writes the binary representation of this scalar to the given
// writer.
func (s *scalar) MarshalTo(w io.Writer) (int, error) {
return marshalling.ScalarMarshalTo(s, w)
}
// UnmarshalFrom reads the binary representation of a scalar from the given
// reader.
func (s *scalar) UnmarshalFrom(r io.Reader) (int, error) {
return marshalling.ScalarUnmarshalFrom(s, r)
}
func newScalarInt(i *big.Int) *scalar {
s := scalar{}
s.setInt(mod.NewInt(i, fullOrder))
return &s
}
// Input:
// a[0]+256*a[1]+...+256^31*a[31] = a
// b[0]+256*b[1]+...+256^31*b[31] = b
// c[0]+256*c[1]+...+256^31*c[31] = c
//
// Output:
// s[0]+256*s[1]+...+256^31*s[31] = (ab+c) mod l
// where l = 2^252 + 27742317777372353535851937790883648493.
func scMulAdd(s, a, b, c *[32]byte) {
a0 := 2097151 & load3(a[:])
a1 := 2097151 & (load4(a[2:]) >> 5)
a2 := 2097151 & (load3(a[5:]) >> 2)
a3 := 2097151 & (load4(a[7:]) >> 7)
a4 := 2097151 & (load4(a[10:]) >> 4)
a5 := 2097151 & (load3(a[13:]) >> 1)
a6 := 2097151 & (load4(a[15:]) >> 6)
a7 := 2097151 & (load3(a[18:]) >> 3)
a8 := 2097151 & load3(a[21:])
a9 := 2097151 & (load4(a[23:]) >> 5)
a10 := 2097151 & (load3(a[26:]) >> 2)
a11 := (load4(a[28:]) >> 7)
b0 := 2097151 & load3(b[:])
b1 := 2097151 & (load4(b[2:]) >> 5)
b2 := 2097151 & (load3(b[5:]) >> 2)
b3 := 2097151 & (load4(b[7:]) >> 7)
b4 := 2097151 & (load4(b[10:]) >> 4)
b5 := 2097151 & (load3(b[13:]) >> 1)
b6 := 2097151 & (load4(b[15:]) >> 6)
b7 := 2097151 & (load3(b[18:]) >> 3)
b8 := 2097151 & load3(b[21:])
b9 := 2097151 & (load4(b[23:]) >> 5)
b10 := 2097151 & (load3(b[26:]) >> 2)
b11 := (load4(b[28:]) >> 7)
c0 := 2097151 & load3(c[:])
c1 := 2097151 & (load4(c[2:]) >> 5)
c2 := 2097151 & (load3(c[5:]) >> 2)
c3 := 2097151 & (load4(c[7:]) >> 7)
c4 := 2097151 & (load4(c[10:]) >> 4)
c5 := 2097151 & (load3(c[13:]) >> 1)
c6 := 2097151 & (load4(c[15:]) >> 6)
c7 := 2097151 & (load3(c[18:]) >> 3)
c8 := 2097151 & load3(c[21:])
c9 := 2097151 & (load4(c[23:]) >> 5)
c10 := 2097151 & (load3(c[26:]) >> 2)
c11 := (load4(c[28:]) >> 7)
var carry [23]int64
s0 := c0 + a0*b0
s1 := c1 + a0*b1 + a1*b0
s2 := c2 + a0*b2 + a1*b1 + a2*b0
s3 := c3 + a0*b3 + a1*b2 + a2*b1 + a3*b0
s4 := c4 + a0*b4 + a1*b3 + a2*b2 + a3*b1 + a4*b0
s5 := c5 + a0*b5 + a1*b4 + a2*b3 + a3*b2 + a4*b1 + a5*b0
s6 := c6 + a0*b6 + a1*b5 + a2*b4 + a3*b3 + a4*b2 + a5*b1 + a6*b0
s7 := c7 + a0*b7 + a1*b6 + a2*b5 + a3*b4 + a4*b3 + a5*b2 + a6*b1 + a7*b0
s8 := c8 + a0*b8 + a1*b7 + a2*b6 + a3*b5 + a4*b4 + a5*b3 + a6*b2 + a7*b1 + a8*b0
s9 := c9 + a0*b9 + a1*b8 + a2*b7 + a3*b6 + a4*b5 + a5*b4 + a6*b3 + a7*b2 + a8*b1 + a9*b0
s10 := c10 + a0*b10 + a1*b9 + a2*b8 + a3*b7 + a4*b6 + a5*b5 + a6*b4 + a7*b3 + a8*b2 + a9*b1 + a10*b0
s11 := c11 + a0*b11 + a1*b10 + a2*b9 + a3*b8 + a4*b7 + a5*b6 + a6*b5 + a7*b4 + a8*b3 + a9*b2 + a10*b1 + a11*b0
s12 := a1*b11 + a2*b10 + a3*b9 + a4*b8 + a5*b7 + a6*b6 + a7*b5 + a8*b4 + a9*b3 + a10*b2 + a11*b1
s13 := a2*b11 + a3*b10 + a4*b9 + a5*b8 + a6*b7 + a7*b6 + a8*b5 + a9*b4 + a10*b3 + a11*b2
s14 := a3*b11 + a4*b10 + a5*b9 + a6*b8 + a7*b7 + a8*b6 + a9*b5 + a10*b4 + a11*b3
s15 := a4*b11 + a5*b10 + a6*b9 + a7*b8 + a8*b7 + a9*b6 + a10*b5 + a11*b4
s16 := a5*b11 + a6*b10 + a7*b9 + a8*b8 + a9*b7 + a10*b6 + a11*b5
s17 := a6*b11 + a7*b10 + a8*b9 + a9*b8 + a10*b7 + a11*b6
s18 := a7*b11 + a8*b10 + a9*b9 + a10*b8 + a11*b7
s19 := a8*b11 + a9*b10 + a10*b9 + a11*b8
s20 := a9*b11 + a10*b10 + a11*b9
s21 := a10*b11 + a11*b10
s22 := a11 * b11
s23 := int64(0)
carry[0] = (s0 + (1 << 20)) >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[2] = (s2 + (1 << 20)) >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[4] = (s4 + (1 << 20)) >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[12] = (s12 + (1 << 20)) >> 21
s13 += carry[12]
s12 -= carry[12] << 21
carry[14] = (s14 + (1 << 20)) >> 21
s15 += carry[14]
s14 -= carry[14] << 21
carry[16] = (s16 + (1 << 20)) >> 21
s17 += carry[16]
s16 -= carry[16] << 21
carry[18] = (s18 + (1 << 20)) >> 21
s19 += carry[18]
s18 -= carry[18] << 21
carry[20] = (s20 + (1 << 20)) >> 21
s21 += carry[20]
s20 -= carry[20] << 21
carry[22] = (s22 + (1 << 20)) >> 21
s23 += carry[22]
s22 -= carry[22] << 21
carry[1] = (s1 + (1 << 20)) >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[3] = (s3 + (1 << 20)) >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[5] = (s5 + (1 << 20)) >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
carry[13] = (s13 + (1 << 20)) >> 21
s14 += carry[13]
s13 -= carry[13] << 21
carry[15] = (s15 + (1 << 20)) >> 21
s16 += carry[15]
s15 -= carry[15] << 21
carry[17] = (s17 + (1 << 20)) >> 21
s18 += carry[17]
s17 -= carry[17] << 21
carry[19] = (s19 + (1 << 20)) >> 21
s20 += carry[19]
s19 -= carry[19] << 21
carry[21] = (s21 + (1 << 20)) >> 21
s22 += carry[21]
s21 -= carry[21] << 21
s11 += s23 * 666643
s12 += s23 * 470296
s13 += s23 * 654183
s14 -= s23 * 997805
s15 += s23 * 136657
s16 -= s23 * 683901
s23 = 0
s10 += s22 * 666643
s11 += s22 * 470296
s12 += s22 * 654183
s13 -= s22 * 997805
s14 += s22 * 136657
s15 -= s22 * 683901
s22 = 0
s9 += s21 * 666643
s10 += s21 * 470296
s11 += s21 * 654183
s12 -= s21 * 997805
s13 += s21 * 136657
s14 -= s21 * 683901
s21 = 0
s8 += s20 * 666643
s9 += s20 * 470296
s10 += s20 * 654183
s11 -= s20 * 997805
s12 += s20 * 136657
s13 -= s20 * 683901
s20 = 0
s7 += s19 * 666643
s8 += s19 * 470296
s9 += s19 * 654183
s10 -= s19 * 997805
s11 += s19 * 136657
s12 -= s19 * 683901
s19 = 0
s6 += s18 * 666643
s7 += s18 * 470296
s8 += s18 * 654183
s9 -= s18 * 997805
s10 += s18 * 136657
s11 -= s18 * 683901
s18 = 0
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[12] = (s12 + (1 << 20)) >> 21
s13 += carry[12]
s12 -= carry[12] << 21
carry[14] = (s14 + (1 << 20)) >> 21
s15 += carry[14]
s14 -= carry[14] << 21
carry[16] = (s16 + (1 << 20)) >> 21
s17 += carry[16]
s16 -= carry[16] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
carry[13] = (s13 + (1 << 20)) >> 21
s14 += carry[13]
s13 -= carry[13] << 21
carry[15] = (s15 + (1 << 20)) >> 21
s16 += carry[15]
s15 -= carry[15] << 21
s5 += s17 * 666643
s6 += s17 * 470296
s7 += s17 * 654183
s8 -= s17 * 997805
s9 += s17 * 136657
s10 -= s17 * 683901
s17 = 0
s4 += s16 * 666643
s5 += s16 * 470296
s6 += s16 * 654183
s7 -= s16 * 997805
s8 += s16 * 136657
s9 -= s16 * 683901
s16 = 0
s3 += s15 * 666643
s4 += s15 * 470296
s5 += s15 * 654183
s6 -= s15 * 997805
s7 += s15 * 136657
s8 -= s15 * 683901
s15 = 0
s2 += s14 * 666643
s3 += s14 * 470296
s4 += s14 * 654183
s5 -= s14 * 997805
s6 += s14 * 136657
s7 -= s14 * 683901
s14 = 0
s1 += s13 * 666643
s2 += s13 * 470296
s3 += s13 * 654183
s4 -= s13 * 997805
s5 += s13 * 136657
s6 -= s13 * 683901
s13 = 0
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = (s0 + (1 << 20)) >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[2] = (s2 + (1 << 20)) >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[4] = (s4 + (1 << 20)) >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[1] = (s1 + (1 << 20)) >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[3] = (s3 + (1 << 20)) >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[5] = (s5 + (1 << 20)) >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = s0 >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[1] = s1 >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[2] = s2 >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[3] = s3 >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[4] = s4 >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[5] = s5 >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[6] = s6 >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[7] = s7 >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[8] = s8 >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[9] = s9 >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[10] = s10 >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[11] = s11 >> 21
s12 += carry[11]
s11 -= carry[11] << 21
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = s0 >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[1] = s1 >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[2] = s2 >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[3] = s3 >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[4] = s4 >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[5] = s5 >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[6] = s6 >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[7] = s7 >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[8] = s8 >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[9] = s9 >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[10] = s10 >> 21
s11 += carry[10]
s10 -= carry[10] << 21
s[0] = byte(s0 >> 0)
s[1] = byte(s0 >> 8)
s[2] = byte((s0 >> 16) | (s1 << 5))
s[3] = byte(s1 >> 3)
s[4] = byte(s1 >> 11)
s[5] = byte((s1 >> 19) | (s2 << 2))
s[6] = byte(s2 >> 6)
s[7] = byte((s2 >> 14) | (s3 << 7))
s[8] = byte(s3 >> 1)
s[9] = byte(s3 >> 9)
s[10] = byte((s3 >> 17) | (s4 << 4))
s[11] = byte(s4 >> 4)
s[12] = byte(s4 >> 12)
s[13] = byte((s4 >> 20) | (s5 << 1))
s[14] = byte(s5 >> 7)
s[15] = byte((s5 >> 15) | (s6 << 6))
s[16] = byte(s6 >> 2)
s[17] = byte(s6 >> 10)
s[18] = byte((s6 >> 18) | (s7 << 3))
s[19] = byte(s7 >> 5)
s[20] = byte(s7 >> 13)
s[21] = byte(s8 >> 0)
s[22] = byte(s8 >> 8)
s[23] = byte((s8 >> 16) | (s9 << 5))
s[24] = byte(s9 >> 3)
s[25] = byte(s9 >> 11)
s[26] = byte((s9 >> 19) | (s10 << 2))
s[27] = byte(s10 >> 6)
s[28] = byte((s10 >> 14) | (s11 << 7))
s[29] = byte(s11 >> 1)
s[30] = byte(s11 >> 9)
s[31] = byte(s11 >> 17)
}
// Hacky scAdd cobbled together rather sub-optimally from scMulAdd.
//
// Input:
// a[0]+256*a[1]+...+256^31*a[31] = a
// c[0]+256*c[1]+...+256^31*c[31] = c
//
// Output:
// s[0]+256*s[1]+...+256^31*s[31] = (a+c) mod l
// where l = 2^252 + 27742317777372353535851937790883648493.
//
func scAdd(s, a, c *[32]byte) {
a0 := 2097151 & load3(a[:])
a1 := 2097151 & (load4(a[2:]) >> 5)
a2 := 2097151 & (load3(a[5:]) >> 2)
a3 := 2097151 & (load4(a[7:]) >> 7)
a4 := 2097151 & (load4(a[10:]) >> 4)
a5 := 2097151 & (load3(a[13:]) >> 1)
a6 := 2097151 & (load4(a[15:]) >> 6)
a7 := 2097151 & (load3(a[18:]) >> 3)
a8 := 2097151 & load3(a[21:])
a9 := 2097151 & (load4(a[23:]) >> 5)
a10 := 2097151 & (load3(a[26:]) >> 2)
a11 := (load4(a[28:]) >> 7)
c0 := 2097151 & load3(c[:])
c1 := 2097151 & (load4(c[2:]) >> 5)
c2 := 2097151 & (load3(c[5:]) >> 2)
c3 := 2097151 & (load4(c[7:]) >> 7)
c4 := 2097151 & (load4(c[10:]) >> 4)
c5 := 2097151 & (load3(c[13:]) >> 1)
c6 := 2097151 & (load4(c[15:]) >> 6)
c7 := 2097151 & (load3(c[18:]) >> 3)
c8 := 2097151 & load3(c[21:])
c9 := 2097151 & (load4(c[23:]) >> 5)
c10 := 2097151 & (load3(c[26:]) >> 2)
c11 := (load4(c[28:]) >> 7)
var carry [23]int64
s0 := c0 + a0
s1 := c1 + a1
s2 := c2 + a2
s3 := c3 + a3
s4 := c4 + a4
s5 := c5 + a5
s6 := c6 + a6
s7 := c7 + a7
s8 := c8 + a8
s9 := c9 + a9
s10 := c10 + a10
s11 := c11 + a11
s12 := int64(0)
s13 := int64(0)
s14 := int64(0)
s15 := int64(0)
s16 := int64(0)
s17 := int64(0)
s18 := int64(0)
s19 := int64(0)
s20 := int64(0)
s21 := int64(0)
s22 := int64(0)
s23 := int64(0)
carry[0] = (s0 + (1 << 20)) >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[2] = (s2 + (1 << 20)) >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[4] = (s4 + (1 << 20)) >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[12] = (s12 + (1 << 20)) >> 21
s13 += carry[12]
s12 -= carry[12] << 21
carry[14] = (s14 + (1 << 20)) >> 21
s15 += carry[14]
s14 -= carry[14] << 21
carry[16] = (s16 + (1 << 20)) >> 21
s17 += carry[16]
s16 -= carry[16] << 21
carry[18] = (s18 + (1 << 20)) >> 21
s19 += carry[18]
s18 -= carry[18] << 21
carry[20] = (s20 + (1 << 20)) >> 21
s21 += carry[20]
s20 -= carry[20] << 21
carry[22] = (s22 + (1 << 20)) >> 21
s23 += carry[22]
s22 -= carry[22] << 21
carry[1] = (s1 + (1 << 20)) >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[3] = (s3 + (1 << 20)) >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[5] = (s5 + (1 << 20)) >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
carry[13] = (s13 + (1 << 20)) >> 21
s14 += carry[13]
s13 -= carry[13] << 21
carry[15] = (s15 + (1 << 20)) >> 21
s16 += carry[15]
s15 -= carry[15] << 21
carry[17] = (s17 + (1 << 20)) >> 21
s18 += carry[17]
s17 -= carry[17] << 21
carry[19] = (s19 + (1 << 20)) >> 21
s20 += carry[19]
s19 -= carry[19] << 21
carry[21] = (s21 + (1 << 20)) >> 21
s22 += carry[21]
s21 -= carry[21] << 21
s11 += s23 * 666643
s12 += s23 * 470296
s13 += s23 * 654183
s14 -= s23 * 997805
s15 += s23 * 136657
s16 -= s23 * 683901
s23 = 0
s10 += s22 * 666643
s11 += s22 * 470296
s12 += s22 * 654183
s13 -= s22 * 997805
s14 += s22 * 136657
s15 -= s22 * 683901
s22 = 0
s9 += s21 * 666643
s10 += s21 * 470296
s11 += s21 * 654183
s12 -= s21 * 997805
s13 += s21 * 136657
s14 -= s21 * 683901
s21 = 0
s8 += s20 * 666643
s9 += s20 * 470296
s10 += s20 * 654183
s11 -= s20 * 997805
s12 += s20 * 136657
s13 -= s20 * 683901
s20 = 0
s7 += s19 * 666643
s8 += s19 * 470296
s9 += s19 * 654183
s10 -= s19 * 997805
s11 += s19 * 136657
s12 -= s19 * 683901
s19 = 0
s6 += s18 * 666643
s7 += s18 * 470296
s8 += s18 * 654183
s9 -= s18 * 997805
s10 += s18 * 136657
s11 -= s18 * 683901
s18 = 0
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[12] = (s12 + (1 << 20)) >> 21
s13 += carry[12]
s12 -= carry[12] << 21
carry[14] = (s14 + (1 << 20)) >> 21
s15 += carry[14]
s14 -= carry[14] << 21
carry[16] = (s16 + (1 << 20)) >> 21
s17 += carry[16]
s16 -= carry[16] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
carry[13] = (s13 + (1 << 20)) >> 21
s14 += carry[13]
s13 -= carry[13] << 21
carry[15] = (s15 + (1 << 20)) >> 21
s16 += carry[15]
s15 -= carry[15] << 21
s5 += s17 * 666643
s6 += s17 * 470296
s7 += s17 * 654183
s8 -= s17 * 997805
s9 += s17 * 136657
s10 -= s17 * 683901
s17 = 0
s4 += s16 * 666643
s5 += s16 * 470296
s6 += s16 * 654183
s7 -= s16 * 997805
s8 += s16 * 136657
s9 -= s16 * 683901
s16 = 0
s3 += s15 * 666643
s4 += s15 * 470296
s5 += s15 * 654183
s6 -= s15 * 997805
s7 += s15 * 136657
s8 -= s15 * 683901
s15 = 0
s2 += s14 * 666643
s3 += s14 * 470296
s4 += s14 * 654183
s5 -= s14 * 997805
s6 += s14 * 136657
s7 -= s14 * 683901
s14 = 0
s1 += s13 * 666643
s2 += s13 * 470296
s3 += s13 * 654183
s4 -= s13 * 997805
s5 += s13 * 136657
s6 -= s13 * 683901
s13 = 0
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = (s0 + (1 << 20)) >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[2] = (s2 + (1 << 20)) >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[4] = (s4 + (1 << 20)) >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[6] = (s6 + (1 << 20)) >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[8] = (s8 + (1 << 20)) >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[10] = (s10 + (1 << 20)) >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[1] = (s1 + (1 << 20)) >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[3] = (s3 + (1 << 20)) >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[5] = (s5 + (1 << 20)) >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[7] = (s7 + (1 << 20)) >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[9] = (s9 + (1 << 20)) >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[11] = (s11 + (1 << 20)) >> 21
s12 += carry[11]
s11 -= carry[11] << 21
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = s0 >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[1] = s1 >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[2] = s2 >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[3] = s3 >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[4] = s4 >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[5] = s5 >> 21
s6 += carry[5]
s5 -= carry[5] << 21
carry[6] = s6 >> 21
s7 += carry[6]
s6 -= carry[6] << 21
carry[7] = s7 >> 21
s8 += carry[7]
s7 -= carry[7] << 21
carry[8] = s8 >> 21
s9 += carry[8]
s8 -= carry[8] << 21
carry[9] = s9 >> 21
s10 += carry[9]
s9 -= carry[9] << 21
carry[10] = s10 >> 21
s11 += carry[10]
s10 -= carry[10] << 21
carry[11] = s11 >> 21
s12 += carry[11]
s11 -= carry[11] << 21
s0 += s12 * 666643
s1 += s12 * 470296
s2 += s12 * 654183
s3 -= s12 * 997805
s4 += s12 * 136657
s5 -= s12 * 683901
s12 = 0
carry[0] = s0 >> 21
s1 += carry[0]
s0 -= carry[0] << 21
carry[1] = s1 >> 21
s2 += carry[1]
s1 -= carry[1] << 21
carry[2] = s2 >> 21
s3 += carry[2]
s2 -= carry[2] << 21
carry[3] = s3 >> 21
s4 += carry[3]
s3 -= carry[3] << 21
carry[4] = s4 >> 21
s5 += carry[4]
s4 -= carry[4] << 21
carry[5] = s5 >> 21