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Signature canonicity #24

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Merged
irfanbozkurt merged 1 commit into from
Dec 22, 2025
Merged

Signature canonicity #24

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13 changes: 13 additions & 0 deletions curve/ecgfp5/scalar_field.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
"encoding/binary"
"math/big"

"github.com/elliottech/poseidon_crypto/field/goldilocks"
gFp5 "github.com/elliottech/poseidon_crypto/field/goldilocks_quintic_extension"
. "github.com/elliottech/poseidon_crypto/int"
)
Expand All @@ -13,6 +14,18 @@
// p = 1067993516717146951041484916571792702745057740581727230159139685185762082554198619328292418486241
type ECgFp5Scalar [5]uint64

func (s ECgFp5Scalar) IsCanonical() bool {
for _, elem := range s {
if elem >= goldilocks.ORDER {
return false
}
}
if ToNonCanonicalBigInt(s).Cmp(ORDER) >= 0 {

Check failure on line 23 in curve/ecgfp5/scalar_field.go

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GitHub Actions / Lint 

S1008: should use 'return ToNonCanonicalBigInt(s).Cmp(ORDER) < 0' instead of 'if ToNonCanonicalBigInt(s).Cmp(ORDER) >= 0 { return false }; return true' (gosimple)
return false
}
return true
}

var (
ORDER, _ = new(big.Int).SetString("1067993516717146951041484916571792702745057740581727230159139685185762082554198619328292418486241", 10)
ZERO = ECgFp5Scalar{}
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8 changes: 8 additions & 0 deletions signature/schnorr/schnorr.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,10 @@ type Signature struct {
E curve.ECgFp5Scalar
}

func (s Signature) IsCanonical() bool {
return s.E.IsCanonical() && s.S.IsCanonical()
}

var ZERO_SIG = Signature{
S: curve.ZERO,
E: curve.ZERO,
Expand Down Expand Up @@ -102,6 +106,10 @@ func Validate(pubKey, hashedMsg, sig []byte) error {
}

func IsSchnorrSignatureValid(pubKey, hashedMsg gFp5.Element, sig Signature) bool {
if !sig.IsCanonical() {
return false
}

pubKeyWs, ok := curve.DecodeFp5AsWeierstrass(pubKey)
if !ok {
return false
Expand Down
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