http://y7yea4pmqqtznb33qiugvysyn2bob5v62e4pvoadoibrwkq3tsddjeyd.onion/zh-hans/glossary/public-key-encryption
So if I encrypted a file with the password "bluetonicmonster, " you would need both the file and the password "bluetonicmonster" to decode it. Public key encryption uses two keys: one to encrypt, and another to decrypt. This has all kinds of useful consequences. For one, it means that you can hand out the key to encrypt messages to you, and as long as you keep the other key secret, anyone with that key can talk to you securely.