RE: Steem Private and Public Keys Demystified 🔐
Posting key - The posting key allows accounts to post, comment, edit, vote, resteem, and follow or mute other accounts. Most users should be logging into Steemit every day with the posting key. You are more likely to have your password or key compromised the more you use it so a limited posting key exists to restrict the damage that a compromised account key would cause.
Active key - The active key is meant for more sensitive tasks such as transferring funds, power up/down transactions, converting Steem Dollars, voting for witnesses, updating profile details and avatar, and placing a market order.
The public posting key is used to authenticate your comment/edit/vote/resteems, etc..., while the public active key authenticates your fund transfers, powerups, etc...
hm. So why would our public keys be exposed (to the public) in our accounts? I understand memo public key because we can have such a use on that (to send steem to someone), so how about posting public keys? I understand that the authentication is needed, so is it possible that I (for example) send an encrypted message to you, with your public posting key, so that your private posting key can decrypt the message?
Public keys are meant to be public, they're not 'exposed' or at risk. If you encrypt a message with my public key (doesn't matter what type of key it is), only ME can decrypt it with my private key. On the other hand, I can SIGN a message with my PRIVATE key and send it to you, and you can use my public key to authenticate that it was ME who signed it.
The posting, active, owner, memo keys are inventions of Steem to allocate different permissions to your account. The public/private key pairs are used by the system, not me or you, to authenticate the author or the transactions.
Maybe one day Steemit will evolve to a stage we can encrypt and decrypt it using its services and enable privacy control of our own keys. That would be nice.