Here's a bintodec function:

    sub bintodec {
        unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
    }
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Taken from the pack manpage.

And this seems to work for a dectobin, although there's probably a faster way w/o using join:

    sub dectobin {
        join '', unpack "B32", pack "N", shift;
    }
[download]