Bluefish - encryption library bug?

I am getting the following error while using encryption with Bluefish & cbc mode. Is it a bug since the function name looks wrong to me strtotupper() - should it be strtoupper().....
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A PHP Error was encountered

Severity: Error

Message: Call to undefined function strtotupper()

Filename: libraries/Encryption.php

Line Number: 302

Backtrace:
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Thanks,
Imtyaz Sumra