Secure communication method and apparatus in passive optical network

A method for secure communication, comprising:

• receiving, by an optical network unit (ONU), a first message sent by an optical line terminal (OLT), wherein the first message comprises a first key algorithm, a certificate of the OLT, and a public key of the OLT, and the first key algorithm is a key algorithm supported by both the OLT and the ONU;
• determining, by the ONU, a shared key based on the first key algorithm and the public key of the OLT after verification on the certificate of the OLT succeeds, wherein the shared key is used to encrypt a session between the OLT and the ONU;
• using, by the ONU, a random number as a private key of the ONU;
• and
• determining, by the ONU, a public key of the ONU based on the first key algorithm and the private key of the ONU;
• and
• sending, by the ONU, a second message to the OLT, wherein the second message comprises a certificate of the ONU and the public key of the ONU, wherein the public key of the ONU and the private key of the ONU, and a public key and a private key corresponding to the certificate of the ONU are two sets of keys, the certificate of the ONU and the public key of the ONU are unencrypted, and the public key of the ONU is used to enable the OLT to determine the shared key.