diff --git a/src/ICSharpCode.SharpZipLib/Encryption/ZipAESStream.cs b/src/ICSharpCode.SharpZipLib/Encryption/ZipAESStream.cs
index ffafee5df..4f649e8a9 100644
--- a/src/ICSharpCode.SharpZipLib/Encryption/ZipAESStream.cs
+++ b/src/ICSharpCode.SharpZipLib/Encryption/ZipAESStream.cs
@@ -163,7 +163,7 @@ private int ReadBufferedData(byte[] buffer, int offset, int count)
 		{
 			int copyCount = Math.Min(count, _transformBufferFreePos - _transformBufferStartPos);
 
-			Array.Copy(_transformBuffer, _transformBufferStartPos, buffer, offset, count);
+			Array.Copy(_transformBuffer, _transformBufferStartPos, buffer, offset, copyCount);
 			_transformBufferStartPos += copyCount;
 
 			return copyCount;