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They will do the same thing for cross chain transactions with other blockchains like BTC and ETC.
Thanks, your explanation helped me a lot to understand it better. So as you posted it is not NEM-exclusive. The approach can be implemented with any other blockchain in principle. Why is there then so much hope in Catapult if it could be used with other projects as well?
I've gotten another question what doesn't really depend on the first one. I run a little web service where registration is needed. Currently you need username password combination. Pretty old school. I consider to implement a simplier login via NEM address but I have no idea how it could work without providing a private key. Any suggestions? I am not a developer but my friend is very capable, so he could implement the idea.