What aspect of public key cryptography makes it especially useful for electronic commerce on the Internet?

Answer 1

Unlike conventional cryptography, public-key cryptography allows two parties to establish secure communication using only insecure communication channels.

You see, conventional (secret-key) encryption allows two parties to communicate over an insecure channel - but they require a secure channel to agree on the encryption key. With public key cryptography, this is no longer necessary - the key negotiation process can be performed over insecure channels too (although there spoofing - the so-called man-in-the-middle attacks - can still be a problem, so the *integrity* of the channel during the key negotiation phase is still important).

Answer 2

I hope this isn't a homework question! ;-)

the reason public key crypto is so useful is how relatively easy and secure it makes transactions.

If we didn't have a cryptography system that was available, all information on the net would be in plain text! This means any bad guys could get your information by simply watching and recording the data as it moves on the Internet.