diff --git a/backend/mpc-system/services/service-party-app/tss-party/main.go b/backend/mpc-system/services/service-party-app/tss-party/main.go
index b75bd655..e613f701 100644
--- a/backend/mpc-system/services/service-party-app/tss-party/main.go
+++ b/backend/mpc-system/services/service-party-app/tss-party/main.go
@@ -223,6 +223,9 @@ func executeKeygen(
 	go func() {
 		defer inWg.Done()
 		scanner := bufio.NewScanner(os.Stdin)
+		// Increase buffer for large messages (TSS messages can be ~200KB)
+		buf := make([]byte, 1024*1024)
+		scanner.Buffer(buf, len(buf))
 		for scanner.Scan() {
 			select {
 			case <-ctx.Done():