I can't much information behind Sesame since I haven't read much on it but Sesame stands for Secure European System for Applications in a Multi-vendor Environment (really stranger name, isn't it? xD). I do know its like Kerberos but can't give much more info on it.
Now back to your question. Sesame uses Public key encryption to distribute secret keys. Which if you are a tech student, you should know what a public key encryption i ;)
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-Geekhawk