xs/vendor/blitter.com/go/kyber/polyvec.go

116 lines
4.1 KiB
Go
Raw Normal View History

// polyvec.go - Vector of Kyber polynomials.
//
// To the extent possible under law, Yawning Angel has waived all copyright
// and related or neighboring rights to the software, using the Creative
// Commons "CC0" public domain dedication. See LICENSE or
// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.
package kyber
type polyVec struct {
vec []*poly
}
// Compress and serialize vector of polynomials.
func (v *polyVec) compress(r []byte) {
var off int
for _, vec := range v.vec {
for j := 0; j < kyberN/8; j++ {
var t [8]uint16
for k := 0; k < 8; k++ {
t[k] = uint16((((uint32(freeze(vec.coeffs[8*j+k])) << 11) + kyberQ/2) / kyberQ) & 0x7ff)
}
r[off+11*j+0] = byte(t[0] & 0xff)
r[off+11*j+1] = byte((t[0] >> 8) | ((t[1] & 0x1f) << 3))
r[off+11*j+2] = byte((t[1] >> 5) | ((t[2] & 0x03) << 6))
r[off+11*j+3] = byte((t[2] >> 2) & 0xff)
r[off+11*j+4] = byte((t[2] >> 10) | ((t[3] & 0x7f) << 1))
r[off+11*j+5] = byte((t[3] >> 7) | ((t[4] & 0x0f) << 4))
r[off+11*j+6] = byte((t[4] >> 4) | ((t[5] & 0x01) << 7))
r[off+11*j+7] = byte((t[5] >> 1) & 0xff)
r[off+11*j+8] = byte((t[5] >> 9) | ((t[6] & 0x3f) << 2))
r[off+11*j+9] = byte((t[6] >> 6) | ((t[7] & 0x07) << 5))
r[off+11*j+10] = byte((t[7] >> 3))
}
off += compressedCoeffSize
}
}
// De-serialize and decompress vector of polynomials; approximate inverse of
// polyVec.compress().
func (v *polyVec) decompress(a []byte) {
var off int
for _, vec := range v.vec {
for j := 0; j < kyberN/8; j++ {
vec.coeffs[8*j+0] = uint16((((uint32(a[off+11*j+0]) | ((uint32(a[off+11*j+1]) & 0x07) << 8)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+1] = uint16(((((uint32(a[off+11*j+1]) >> 3) | ((uint32(a[off+11*j+2]) & 0x3f) << 5)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+2] = uint16(((((uint32(a[off+11*j+2]) >> 6) | ((uint32(a[off+11*j+3]) & 0xff) << 2) | ((uint32(a[off+11*j+4]) & 0x01) << 10)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+3] = uint16(((((uint32(a[off+11*j+4]) >> 1) | ((uint32(a[off+11*j+5]) & 0x0f) << 7)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+4] = uint16(((((uint32(a[off+11*j+5]) >> 4) | ((uint32(a[off+11*j+6]) & 0x7f) << 4)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+5] = uint16(((((uint32(a[off+11*j+6]) >> 7) | ((uint32(a[off+11*j+7]) & 0xff) << 1) | ((uint32(a[off+11*j+8]) & 0x03) << 9)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+6] = uint16(((((uint32(a[off+11*j+8]) >> 2) | ((uint32(a[off+11*j+9]) & 0x1f) << 6)) * kyberQ) + 1024) >> 11)
vec.coeffs[8*j+7] = uint16(((((uint32(a[off+11*j+9]) >> 5) | ((uint32(a[off+11*j+10]) & 0xff) << 3)) * kyberQ) + 1024) >> 11)
}
off += compressedCoeffSize
}
}
// Serialize vector of polynomials.
func (v *polyVec) toBytes(r []byte) {
for i, p := range v.vec {
p.toBytes(r[i*polySize:])
}
}
// De-serialize vector of polynomials; inverse of polyVec.toBytes().
func (v *polyVec) fromBytes(a []byte) {
for i, p := range v.vec {
p.fromBytes(a[i*polySize:])
}
}
// Apply forward NTT to all elements of a vector of polynomials.
func (v *polyVec) ntt() {
for _, p := range v.vec {
p.ntt()
}
}
// Apply inverse NTT to all elements of a vector of polynomials.
func (v *polyVec) invntt() {
for _, p := range v.vec {
p.invntt()
}
}
// Pointwise multiply elements of a and b and accumulate into p.
func (p *poly) pointwiseAcc(a, b *polyVec) {
hardwareAccelImpl.pointwiseAccFn(p, a, b)
}
// Add vectors of polynomials.
func (v *polyVec) add(a, b *polyVec) {
for i, p := range v.vec {
p.add(a.vec[i], b.vec[i])
}
}
// Get compressed and serialized size in bytes.
func (v *polyVec) compressedSize() int {
return len(v.vec) * compressedCoeffSize
}
func pointwiseAccRef(p *poly, a, b *polyVec) {
for j := 0; j < kyberN; j++ {
t := montgomeryReduce(4613 * uint32(b.vec[0].coeffs[j])) // 4613 = 2^{2*18} % q
p.coeffs[j] = montgomeryReduce(uint32(a.vec[0].coeffs[j]) * uint32(t))
for i := 1; i < len(a.vec); i++ { // len(a.vec) == kyberK
t = montgomeryReduce(4613 * uint32(b.vec[i].coeffs[j]))
p.coeffs[j] += montgomeryReduce(uint32(a.vec[i].coeffs[j]) * uint32(t))
}
p.coeffs[j] = barrettReduce(p.coeffs[j])
}
}