mirror of
https://github.com/luxfi/crypto.git
synced 2026-07-27 01:54:50 +00:00
Hanzo AI
22b99bca01
The Banderwagon prime-order group used by Verkle / IPA had been vendored internally under lux/crypto/ipa/banderwagon. Extract it to lux/crypto/banderwagon as the canonical Lux public surface; rewrite all internal ipa callers (prover, verifier, config, multiproof, common, transcript, test_helper, tests) to import from the canonical home. - Provenance comment on every file: github.com/crate-crypto/go-ipa (Apache-2.0 / MIT dual). Adds LICENSE-GO-IPA-APACHE2 and LICENSE-GO-IPA-MIT alongside the package. - Element / Generator / Identity / Fr / MSMPrecomp / PrecompPoint / CompressedSize / UncompressedSize / SetBytes / SetBytesUncompressed / ElementsToBytes / BatchToBytesUncompressed / BatchNormalize / MapToScalarField / BatchMapToScalarField / Add / Sub / Double / Neg / ScalarMul / MultiExp now have one and only one home: lux/crypto/banderwagon. - Verkle (parallel branch) will switch its banderwagon import to this canonical surface. - KAT vectors from the upstream go-ipa Verkle reference suite preserved (TestEncodingFixedVectors, TestPointAtInfinityComponent) plus all precomp MSM-vs-gnark random-round tests (1000 * NumCPU rounds). Tests: go test ./banderwagon/... ./ipa/... — all PASS (banderwagon 27s, ipa 16s, ipa/bandersnatch 24s, fp/fr 4s+2s, common 3s).
88 lines
1.9 KiB
Go
88 lines
1.9 KiB
Go
package common
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import (
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"bytes"
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"crypto/sha256"
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"hash"
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"github.com/luxfi/crypto/banderwagon"
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"github.com/luxfi/crypto/ipa/bandersnatch/fr"
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)
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// The transcript is used to create challenge scalars.
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// See: Fiat-Shamir
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type Transcript struct {
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state hash.Hash
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buff *bytes.Buffer
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}
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func NewTranscript(label string) *Transcript {
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digest := sha256.New()
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digest.Write([]byte(label))
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transcript := &Transcript{
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state: digest,
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buff: bytes.NewBuffer(make([]byte, 0, 1024)),
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}
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return transcript
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}
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func (t *Transcript) AppendMessage(message []byte, label []byte) {
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t.buff.Write(label)
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t.buff.Write(message)
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}
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// Appends a Scalar to the transcript
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//
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// Converts the scalar to 32 bytes, then appends it to
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// the state
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func (t *Transcript) AppendScalar(scalar *fr.Element, label []byte) {
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tmpBytes := scalar.BytesLE()
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t.AppendMessage(tmpBytes[:], label)
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}
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// Appends a Point to the transcript
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//
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// Compresses the Point into a 32 byte slice, then appends it to
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// the state
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func (t *Transcript) AppendPoint(point *banderwagon.Element, label []byte) {
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tmp_bytes := point.Bytes()
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t.AppendMessage(tmp_bytes[:], label)
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}
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func (t *Transcript) DomainSep(label []byte) {
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t.buff.Write(label)
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}
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// Computes a challenge based off of the state of the transcript
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//
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// Hash the transcript state, then reduce the hash modulo the size of the
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// scalar field
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//
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// Note that calling the transcript twice, will yield two different challenges
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func (t *Transcript) ChallengeScalar(label []byte) fr.Element {
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t.DomainSep(label)
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t.state.Write(t.buff.Bytes())
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t.buff.Reset()
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// Reverse the endian so we are using little-endian
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// SetBytes interprets the bytes in Big Endian
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bytes := t.state.Sum(nil)
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var tmp fr.Element
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tmp.SetBytesLE(bytes)
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// Clear the state
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t.state.Reset()
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// Add the new challenge to the state
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// Which "summarises" the previous state before we cleared it
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t.AppendScalar(&tmp, label)
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// Return the new challenge
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return tmp
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}
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