🚀 go-pugleaf

I am planning to release a small utility program as shareware. For
that I'd like to have some method of generating reasonably sized
registration keys that I can check for validity in the actual program
without revealing how the key is made.

The method I am thinking of is to make the registration key a signed
message of the users name (or of the checksum of users name). The user
program should be able to verify the signature without much
calculation, code and data.

The algorithm need not be very strong. Just enough strong that not
many people that have a hobby of breaking the keys want to generate a
key of their own for name "Harry Hacker" or something.

I'd very much appreciate suggestions for algorithms, estimates on
their difficulty to break and pointers to ready source or the source
itself to the email address given below and in the reply-to header
line.

Thank you.
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Marko Kohtala - INTERNET:Marko.Kohtala@hut.fi, mkohtala@otax.tky.hut.fi
Student at (not representative of) the Helsinki University of Technology