diff --git a/src_io_utils/pistreampacker.cpp b/src_io_utils/pistreampacker.cpp
index 1d4d533d..60500cc0 100644
--- a/src_io_utils/pistreampacker.cpp
+++ b/src_io_utils/pistreampacker.cpp
@@ -141,12 +141,21 @@ void PIStreamPacker::received(const PIByteArray & data) {
 			if (packet.size_s() == packet_size) {
 				PIByteArray cd;
 				if (crypt_frag) {
+					//piCout << "decrypt frags ..." << packet_size;
 					while (packet.size_s() >= 4) {
+						//piCout << "decrypt frags take data ...";
 						PIByteArray frag;
+						//piCout << "decrypt frags take data done" << frag.size_s();
 						packet >> frag;
+						if (frag.isEmpty()) {
+							//piCout << "decrypt frags corrupt, break";
+							cd.clear();
+							break;
+						}
 						cd.append(decryptData(frag));
-						//piCout << "crypt_frag receive add frag" << frag.size_s();
+						//piCout << "decrypt frags add" << frag.size_s();
 					}
+					//piCout << "decrypt frags done" << cd.size();
 				} else {
 					cd = decryptData(packet);
 				}
diff --git a/src_main/core/pibytearray.cpp b/src_main/core/pibytearray.cpp
index e7a6c489..3408d3ff 100755
--- a/src_main/core/pibytearray.cpp
+++ b/src_main/core/pibytearray.cpp
@@ -375,8 +375,14 @@ std::ostream &operator <<(std::ostream & s, const PIByteArray & ba) {
 
 
 PIByteArray & operator >>(PIByteArray & s, PIByteArray & v) {
+	if (s.size_s() < 4) {
+		s.clear();
+		v.clear();
+		return s;
+	}
 	assert(s.size_s() >= 4);
-	int sz; s >> sz;
+	int sz = 0;
+	s >> sz;
 	if (sz > s.size_s()) {
 		piCout << "[PIByteArray] Warning: operator >> wants too much data, discard!";
 		s.clear();
@@ -384,7 +390,9 @@ PIByteArray & operator >>(PIByteArray & s, PIByteArray & v) {
 		return s;
 	}
 	v.resize(sz);
-	if (sz > 0) memcpy(v.data(), s.data(), v.size());
-	s.remove(0, v.size());
+	if (sz > 0) {
+		memcpy(v.data(), s.data(), v.size());
+		s.remove(0, v.size());
+	}
 	return s;
 }