ceremonyclient/nekryptology/pkg/signatures/schnorr/mina/roinput.go

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2023-07-05 05:32:28 +00:00
//
// Copyright Coinbase, Inc. All Rights Reserved.
//
// SPDX-License-Identifier: Apache-2.0
//
package mina
import (
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/core/curves/native/pasta/fp"
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/core/curves/native/pasta/fq"
)
// Handles the packing of bits and fields according to Mina spec
type roinput struct {
fields []*fp.Fp
bits *BitVector
}
var conv = map[bool]int{
true: 1,
false: 0,
}
func (r *roinput) Init(fields int, bytes int) *roinput {
r.fields = make([]*fp.Fp, 0, fields)
r.bits = NewBitVector(make([]byte, bytes), 0)
return r
}
func (r *roinput) Clone() *roinput {
t := new(roinput)
t.fields = make([]*fp.Fp, len(r.fields))
for i, f := range r.fields {
t.fields[i] = new(fp.Fp).Set(f)
}
buffer := r.bits.Bytes()
data := make([]byte, len(buffer))
copy(data, buffer)
t.bits = NewBitVector(data, r.bits.Length())
return t
}
func (r *roinput) AddFp(fp *fp.Fp) {
r.fields = append(r.fields, fp)
}
func (r *roinput) AddFq(fq *fq.Fq) {
scalar := fq.ToRaw()
// Mina handles fields as 255 bit numbers
// with each field we lose a bit
for i := 0; i < 255; i++ {
limb := i / 64
idx := i % 64
b := (scalar[limb] >> idx) & 1
r.bits.Append(byte(b))
}
}
func (r *roinput) AddBit(b bool) {
r.bits.Append(byte(conv[b]))
}
func (r *roinput) AddBytes(input []byte) {
for _, b := range input {
for i := 0; i < 8; i++ {
r.bits.Append(byte((b >> i) & 1))
}
}
}
func (r *roinput) AddUint32(x uint32) {
for i := 0; i < 32; i++ {
r.bits.Append(byte((x >> i) & 1))
}
}
func (r *roinput) AddUint64(x uint64) {
for i := 0; i < 64; i++ {
r.bits.Append(byte((x >> i) & 1))
}
}
func (r roinput) Bytes() []byte {
out := make([]byte, (r.bits.Length()+7)/8+32*len(r.fields))
res := NewBitVector(out, 0)
// Mina handles fields as 255 bit numbers
// with each field we lose a bit
for _, f := range r.fields {
buf := f.ToRaw()
for i := 0; i < 255; i++ {
limb := i / 64
idx := i % 64
b := (buf[limb] >> idx) & 1
res.Append(byte(b))
}
}
for i := 0; i < r.bits.Length(); i++ {
res.Append(r.bits.Element(i))
}
return out
}
func (r roinput) Fields() []*fp.Fp {
fields := make([]*fp.Fp, 0, len(r.fields)+r.bits.Length()/256)
for _, f := range r.fields {
fields = append(fields, new(fp.Fp).Set(f))
}
const maxChunkSize = 254
bitsConsumed := 0
bitIdx := 0
for bitsConsumed < r.bits.Length() {
var chunk [4]uint64
remaining := r.bits.Length() - bitsConsumed
var chunkSizeInBits int
if remaining > maxChunkSize {
chunkSizeInBits = maxChunkSize
} else {
chunkSizeInBits = remaining
}
for i := 0; i < chunkSizeInBits; i++ {
limb := i >> 6
idx := i & 0x3F
b := r.bits.Element(bitIdx)
chunk[limb] |= uint64(b) << idx
bitIdx++
}
fields = append(fields, new(fp.Fp).SetRaw(&chunk))
bitsConsumed += chunkSizeInBits
}
return fields
}