As far as I can tell, using your bit shift assumes two things that I don't have.

The first is that my string is a decimal number. It isn't. I don't know what would happen if you shifted a string filled with hex by 1.

The second is, that my hex string would fit inside a scalar. Perl numbers are limited to 64 bits, and as I mentioned, this string is 104 bits. (When converted from hex to a binary stream.)

As for the length thing, yes, that is another way to do it, I was just going for simple at the time, and I didn't want to lookup length.
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Kwyjibo. A big, dumb, balding North American ape. With no chin.