For Bitcoin, BIP 70 was proposed (and quite widely implemented) to take care of a lot of these issues. I assume many other cash-style cryptocurrencies have some

For Bitcoin, BIP 70 was proposed (and quite widely implemented) to take care of a lot of these issues. I assume many other cash-style cryptocurrencies have something similar these days. https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0070.mediawi...