diff --git a/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java b/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java
index 240fb74f..0c7187f2 100644
--- a/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java
+++ b/src/main/java/com/licel/jcardsim/crypto/ByteContainer.java
@@ -106,7 +106,7 @@ public void setBytes(byte[] buff) {
      * @param length length of data in byte array
      */
     public void setBytes(byte[] buff, short offset, short length) {
-        if (data == null) {
+        if (data == null || (short) data.length != length) {
             switch (memoryType) {
                 case JCSystem.MEMORY_TYPE_TRANSIENT_DESELECT:
                     data = JCSystem.makeTransientByteArray(length, JCSystem.CLEAR_ON_DESELECT);
@@ -121,7 +121,7 @@ public void setBytes(byte[] buff, short offset, short length) {
         }
         Util.arrayCopy(buff, offset, data, (short) 0, length);
         // current length
-        this.length = length;
+        this.length = (short) data.length;
     }
 
     /**