base64 is meant for encoding high-bit data into a form suitable for transmission under the 7bit rules. It has nothing to do with compression. If you want to compress a 64-byte string of 0's and 1's, use pack .

# The sender packs it
my $p = pack 'b4' , $str ;

# And the receiver unpacks it like this:
print unpack 'b4', $p;
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