Just to clarify other people's responses to make this ultra clear for people learning: - stuff encrypted with the private key can only be decrypted using the p

Just to clarify other people's responses to make this ultra clear for people learning: - stuff encrypted with the private key can only be decrypted using the public key. - stuff encrypted with the public key can only be decrypted using the private key. This is why the public key can be distributed around freely and anyone can use it to encrypt, because only the person with the private key can decrypt it (and this is why you really need to keep your private key secure!) The flip side is anyone can decrypt something encrypted with the private key (since the public key is widely known). But this is how we can verify that the other server really is who they say they are - remember that the public key can only decrypt stuff encrypted with the private key, so if we can decrypt something from the server then we know that they encrypted it using the private key and are therefore probably legit (...or the private key got leaked or CIA/Snowdon etc) Enjoy learning! :)