ix important issue (#909)

drand · Jan 31, 2022 · 9627b87 · 9627b87
1 parent ddb8677
commit 9627b87
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/chain/verify.go b/chain/verify.go
@@ -43,3 +43,7 @@ func (v Verifier) VerifyBeacon(b Beacon, pubkey kyber.Point) error {
 
 	return key.Scheme.VerifyRecovered(pubkey, msg, b.Signature)
 }
+
+func (v Verifier) IsPrevSigMeaningful() bool {
+	return !v.scheme.DecouplePrevSig
+}
diff --git a/client/verify.go b/client/verify.go
@@ -180,8 +180,10 @@ func (v *verifyingClient) getTrustedPreviousSignature(ctx context.Context, round
 }
 
 func (v *verifyingClient) verify(ctx context.Context, info *chain.Info, r *RandomData) (err error) {
+	checkPrevSignature := v.opts.strict || (v.verifier.IsPrevSigMeaningful() && r.PreviousSignature == nil)
 	ps := r.PreviousSignature
-	if v.opts.strict || r.PreviousSignature == nil {
+
+	if checkPrevSignature {
 		ps, err = v.getTrustedPreviousSignature(ctx, r.Round())
 		if err != nil {
 			return