Many years ago I was involved in finding and fixing a messaging bug that only appeared when the base64 encoded payload had a length that was a multiple of 87 by

Many years ago I was involved in finding and fixing a messaging bug that only appeared when the base64 encoded payload had a length that was a multiple of 87 bytes (it might have been some other value - it was 15+ years ago). Bug was in a C++ base64 encoder component.